diff --git a/js/console_test.go b/js/console_test.go
index aa8b938ab9f..2d65af9cbdf 100644
--- a/js/console_test.go
+++ b/js/console_test.go
@@ -73,7 +73,7 @@ func TestConsoleContext(t *testing.T) {
 func getSimpleRunner(filename, data string, opts ...interface{}) (*Runner, error) {
 	var (
 		fs     = afero.NewMemMapFs()
-		rtOpts = lib.RuntimeOptions{}
+		rtOpts = lib.RuntimeOptions{CompatibilityMode: null.NewString("base", true)}
 	)
 	for _, o := range opts {
 		switch opt := o.(type) {
@@ -117,7 +117,7 @@ func TestConsole(t *testing.T) {
 				args, result := args, result
 				t.Run(args, func(t *testing.T) {
 					r, err := getSimpleRunner("/script.js", fmt.Sprintf(
-						`export default function() { console.%s(%s); }`,
+						`exports.default = function() { console.%s(%s); }`,
 						name, args,
 					))
 					assert.NoError(t, err)
@@ -209,7 +209,7 @@ func TestFileConsole(t *testing.T) {
 							}
 							r, err := getSimpleRunner("/script",
 								fmt.Sprintf(
-									`export default function() { console.%s(%s); }`,
+									`exports.default = function() { console.%s(%s); }`,
 									name, args,
 								))
 							assert.NoError(t, err)
diff --git a/js/module_loading_test.go b/js/module_loading_test.go
index 6e64c62dc2c..57b0f5728c3 100644
--- a/js/module_loading_test.go
+++ b/js/module_loading_test.go
@@ -28,6 +28,7 @@ import (
 
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
+	null "gopkg.in/guregu/null.v3"
 
 	"github.com/loadimpact/k6/lib"
 	"github.com/loadimpact/k6/lib/testutils/httpmultibin"
@@ -99,7 +100,7 @@ func TestLoadOnceGlobalVars(t *testing.T) {
 					throw new Error("A() != B()    (" + A() + ") != (" + B() + ")");
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 			require.NoError(t, err)
 
 			arc := r1.MakeArchive()
@@ -148,7 +149,7 @@ func TestLoadExportsIsUsableInModule(t *testing.T) {
 					throw new Error("wrong value of B() " + B());
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	arc := r1.MakeArchive()
@@ -194,7 +195,7 @@ func TestLoadDoesntBreakHTTPGet(t *testing.T) {
 					throw new Error("wrong status "+ resp.status);
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	require.NoError(t, r1.SetOptions(lib.Options{Hosts: tb.Dialer.Hosts}))
@@ -239,7 +240,7 @@ func TestLoadGlobalVarsAreNotSharedBetweenVUs(t *testing.T) {
 					throw new Error("wrong value of a " + a);
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	arc := r1.MakeArchive()
@@ -302,7 +303,7 @@ func TestLoadCycle(t *testing.T) {
 	`), os.ModePerm))
 	data, err := afero.ReadFile(fs, "/main.js")
 	require.NoError(t, err)
-	r1, err := getSimpleRunner("/main.js", string(data), fs)
+	r1, err := getSimpleRunner("/main.js", string(data), fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	arc := r1.MakeArchive()
@@ -364,7 +365,7 @@ func TestLoadCycleBinding(t *testing.T) {
 					throw new Error("Wrong value of bar() "+ barMessage);
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	arc := r1.MakeArchive()
@@ -428,7 +429,7 @@ func TestBrowserified(t *testing.T) {
 					throw new Error("bravo.B() != 'b'    (" + bravo.B() + ") != 'b'");
 				}
 			}
-		`, fs)
+		`, fs, lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")})
 	require.NoError(t, err)
 
 	arc := r1.MakeArchive()
@@ -459,7 +460,7 @@ func TestLoadingUnexistingModuleDoesntPanic(t *testing.T) {
 			} catch (err) {
 				b = "correct";
 			}
-			export default function() {
+			exports.default = function() {
 				if (b != "correct") {
 					throw new Error("wrong b "+ JSON.stringify(b));
 				}
diff --git a/js/runner_test.go b/js/runner_test.go
index dbc3a15d58c..1b90bc8f770 100644
--- a/js/runner_test.go
+++ b/js/runner_test.go
@@ -63,8 +63,8 @@ import (
 func TestRunnerNew(t *testing.T) {
 	t.Run("Valid", func(t *testing.T) {
 		r, err := getSimpleRunner("/script.js", `
-			let counter = 0;
-			export default function() { counter++; }
+			var counter = 0;
+			exports.default = function() { counter++; }
 		`)
 		assert.NoError(t, err)
 
@@ -93,7 +93,7 @@ func TestRunnerNew(t *testing.T) {
 }
 
 func TestRunnerGetDefaultGroup(t *testing.T) {
-	r1, err := getSimpleRunner("/script.js", `export default function() {};`)
+	r1, err := getSimpleRunner("/script.js", `exports.default = function() {};`)
 	if assert.NoError(t, err) {
 		assert.NotNil(t, r1.GetDefaultGroup())
 	}
@@ -105,7 +105,7 @@ func TestRunnerGetDefaultGroup(t *testing.T) {
 }
 
 func TestRunnerOptions(t *testing.T) {
-	r1, err := getSimpleRunner("/script.js", `export default function() {};`)
+	r1, err := getSimpleRunner("/script.js", `exports.default = function() {};`)
 	if !assert.NoError(t, err) {
 		return
 	}
@@ -135,10 +135,10 @@ func TestOptionsSettingToScript(t *testing.T) {
 
 	optionVariants := []string{
 		"",
-		"let options = null;",
-		"let options = undefined;",
-		"let options = {};",
-		"let options = {teardownTimeout: '1s'};",
+		"var options = null;",
+		"var options = undefined;",
+		"var options = {};",
+		"var options = {teardownTimeout: '1s'};",
 	}
 
 	for i, variant := range optionVariants {
@@ -146,7 +146,7 @@ func TestOptionsSettingToScript(t *testing.T) {
 		t.Run(fmt.Sprintf("Variant#%d", i), func(t *testing.T) {
 			t.Parallel()
 			data := variant + `
-					export default function() {
+					exports.default = function() {
 						if (!options) {
 							throw new Error("Expected options to be defined!");
 						}
@@ -178,8 +178,9 @@ func TestOptionsSettingToScript(t *testing.T) {
 func TestOptionsPropagationToScript(t *testing.T) {
 	t.Parallel()
 	data := `
-			export let options = { setupTimeout: "1s", myOption: "test" };
-			export default function() {
+			var options = { setupTimeout: "1s", myOption: "test" };
+			exports.options = options;
+			exports.default = function() {
 				if (options.external) {
 					throw new Error("Unexpected property external!");
 				}
@@ -203,7 +204,7 @@ func TestOptionsPropagationToScript(t *testing.T) {
 	require.Equal(t, expScriptOptions, r2.GetOptions())
 
 	newOptions := lib.Options{SetupTimeout: types.NullDurationFrom(3 * time.Second)}
-	r2.SetOptions(newOptions)
+	require.NoError(t, r2.SetOptions(newOptions))
 	require.Equal(t, newOptions, r2.GetOptions())
 
 	testdata := map[string]*Runner{"Source": r1, "Archive": r2}
@@ -229,11 +230,11 @@ func TestMetricName(t *testing.T) {
 	defer tb.Cleanup()
 
 	script := tb.Replacer.Replace(`
-		import { Counter } from "k6/metrics";
+		var Counter = require("k6/metrics").Counter;
 
-		let myCounter = new Counter("not ok name @");
+		var myCounter = new Counter("not ok name @");
 
-		export default function(data) {
+		exports.default = function(data) {
 			myCounter.add(1);
 		}
 	`)
@@ -247,9 +248,9 @@ func TestSetupDataIsolation(t *testing.T) {
 	defer tb.Cleanup()
 
 	script := tb.Replacer.Replace(`
-		import { Counter } from "k6/metrics";
+		var Counter = require("k6/metrics").Counter;
 
-		export let options = {
+		exports.options = {
 			execution: {
 				shared_iters: {
 					type: "shared-iterations",
@@ -260,13 +261,13 @@ func TestSetupDataIsolation(t *testing.T) {
 			teardownTimeout: "5s",
 			setupTimeout: "5s",
 		};
-		let myCounter = new Counter("mycounter");
+		var myCounter = new Counter("mycounter");
 
-		export function setup() {
+		exports.setup = function() {
 			return { v: 0 };
 		}
 
-		export default function(data) {
+		exports.default = function(data) {
 			if (data.v !== __ITER) {
 				throw new Error("default: wrong data for iter " + __ITER + ": " + JSON.stringify(data));
 			}
@@ -274,7 +275,7 @@ func TestSetupDataIsolation(t *testing.T) {
 			myCounter.add(1);
 		}
 
-		export function teardown(data) {
+		exports.teardown = function(data) {
 			if (data.v !== 0) {
 				throw new Error("teardown: wrong data: " + data.v);
 			}
@@ -355,17 +356,17 @@ func testSetupDataHelper(t *testing.T, data string) {
 
 func TestSetupDataReturnValue(t *testing.T) {
 	testSetupDataHelper(t, `
-	export let options = { setupTimeout: "1s", teardownTimeout: "1s" };
-	export function setup() {
+	exports.options = { setupTimeout: "1s", teardownTimeout: "1s" };
+	exports.setup = function() {
 		return 42;
 	}
-	export default function(data) {
+	exports.default = function(data) {
 		if (data != 42) {
 			throw new Error("default: wrong data: " + JSON.stringify(data))
 		}
 	};
 
-	export function teardown(data) {
+	exports.teardown = function(data) {
 		if (data != 42) {
 			throw new Error("teardown: wrong data: " + JSON.stringify(data))
 		}
@@ -374,14 +375,14 @@ func TestSetupDataReturnValue(t *testing.T) {
 
 func TestSetupDataNoSetup(t *testing.T) {
 	testSetupDataHelper(t, `
-	export let options = { setupTimeout: "1s", teardownTimeout: "1s" };
-	export default function(data) {
+	exports.options = { setupTimeout: "1s", teardownTimeout: "1s" };
+	exports.default = function(data) {
 		if (data !== undefined) {
 			throw new Error("default: wrong data: " + JSON.stringify(data))
 		}
 	};
 
-	export function teardown(data) {
+	exports.teardown = function(data) {
 		if (data !== undefined) {
 			console.log(data);
 			throw new Error("teardown: wrong data: " + JSON.stringify(data))
@@ -392,7 +393,7 @@ func TestSetupDataNoSetup(t *testing.T) {
 func TestConsoleInInitContext(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
 			console.log("1");
-			export default function(data) {
+			exports.default = function(data) {
 			};
 		`)
 	require.NoError(t, err)
@@ -416,15 +417,15 @@ func TestConsoleInInitContext(t *testing.T) {
 
 func TestSetupDataNoReturn(t *testing.T) {
 	testSetupDataHelper(t, `
-	export let options = { setupTimeout: "1s", teardownTimeout: "1s" };
-	export function setup() { }
-	export default function(data) {
+	exports.options = { setupTimeout: "1s", teardownTimeout: "1s" };
+	exports.setup = function() { }
+	exports.default = function(data) {
 		if (data !== undefined) {
 			throw new Error("default: wrong data: " + JSON.stringify(data))
 		}
 	};
 
-	export function teardown(data) {
+	exports.teardown = function(data) {
 		if (data !== undefined) {
 			throw new Error("teardown: wrong data: " + JSON.stringify(data))
 		}
@@ -439,11 +440,12 @@ func TestRunnerIntegrationImports(t *testing.T) {
 			"k6/metrics",
 			"k6/html",
 		}
+		rtOpts := lib.RuntimeOptions{CompatibilityMode: null.StringFrom("extended")}
 		for _, mod := range modules {
 			mod := mod
 			t.Run(mod, func(t *testing.T) {
 				t.Run("Source", func(t *testing.T) {
-					_, err := getSimpleRunner("/script.js", fmt.Sprintf(`import "%s"; export default function() {}`, mod))
+					_, err := getSimpleRunner("/script.js", fmt.Sprintf(`import "%s"; exports.default = function() {}`, mod), rtOpts)
 					assert.NoError(t, err)
 				})
 			})
@@ -453,7 +455,7 @@ func TestRunnerIntegrationImports(t *testing.T) {
 	t.Run("Files", func(t *testing.T) {
 		fs := afero.NewMemMapFs()
 		require.NoError(t, fs.MkdirAll("/path/to", 0755))
-		require.NoError(t, afero.WriteFile(fs, "/path/to/lib.js", []byte(`export default "hi!";`), 0644))
+		require.NoError(t, afero.WriteFile(fs, "/path/to/lib.js", []byte(`exports.default = "hi!";`), 0644))
 
 		testdata := map[string]struct{ filename, path string }{
 			"Absolute":       {"/path/script.js", "/path/to/lib.js"},
@@ -466,8 +468,8 @@ func TestRunnerIntegrationImports(t *testing.T) {
 			name, data := name, data
 			t.Run(name, func(t *testing.T) {
 				r1, err := getSimpleRunner(data.filename, fmt.Sprintf(`
-					import hi from "%s";
-					export default function() {
+					var hi = require("%s").default;
+					exports.default = function() {
 						if (hi != "hi!") { throw new Error("incorrect value"); }
 					}`, data.path), fs)
 				require.NoError(t, err)
@@ -495,8 +497,8 @@ func TestRunnerIntegrationImports(t *testing.T) {
 
 func TestVURunContext(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-		export let options = { vus: 10 };
-		export default function() { fn(); }
+		exports.options = { vus: 10 };
+		exports.default = function() { fn(); }
 		`)
 	require.NoError(t, err)
 	r1.SetOptions(r1.GetOptions().Apply(lib.Options{Throw: null.BoolFrom(true)}))
@@ -547,7 +549,7 @@ func TestVURunInterrupt(t *testing.T) {
 	}
 
 	r1, err := getSimpleRunner("/script.js", `
-		export default function() { while(true) {} }
+		exports.default = function() { while(true) {} }
 		`)
 	require.NoError(t, err)
 	require.NoError(t, r1.SetOptions(lib.Options{Throw: null.BoolFrom(true)}))
@@ -585,7 +587,7 @@ func TestVURunInterruptDoesntPanic(t *testing.T) {
 	}
 
 	r1, err := getSimpleRunner("/script.js", `
-		export default function() { while(true) {} }
+		exports.default = function() { while(true) {} }
 		`)
 	require.NoError(t, err)
 	require.NoError(t, r1.SetOptions(lib.Options{Throw: null.BoolFrom(true)}))
@@ -632,8 +634,8 @@ func TestVURunInterruptDoesntPanic(t *testing.T) {
 
 func TestVUIntegrationGroups(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-		import { group } from "k6";
-		export default function() {
+		var group = require("k6").group;
+		exports.default = function() {
 			fnOuter();
 			group("my group", function() {
 				fnInner();
@@ -691,10 +693,10 @@ func TestVUIntegrationGroups(t *testing.T) {
 
 func TestVUIntegrationMetrics(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-		import { group } from "k6";
-		import { Trend } from "k6/metrics";
-		let myMetric = new Trend("my_metric");
-		export default function() { myMetric.add(5); }
+		var group = require("k6").group;
+		var Trend = require("k6/metrics").Trend;
+		var myMetric = new Trend("my_metric");
+		exports.default = function() { myMetric.add(5); }
 		`)
 	require.NoError(t, err)
 
@@ -766,8 +768,8 @@ func TestVUIntegrationInsecureRequests(t *testing.T) {
 		data := data
 		t.Run(name, func(t *testing.T) {
 			r1, err := getSimpleRunner("/script.js", `
-					import http from "k6/http";
-					export default function() { http.get("https://expired.badssl.com/"); }
+					var http = require("k6/http");;
+					exports.default = function() { http.get("https://expired.badssl.com/"); }
 				`)
 			require.NoError(t, err)
 			require.NoError(t, r1.SetOptions(lib.Options{Throw: null.BoolFrom(true)}.Apply(data.opts)))
@@ -803,8 +805,8 @@ func TestVUIntegrationInsecureRequests(t *testing.T) {
 
 func TestVUIntegrationBlacklistOption(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-					import http from "k6/http";
-					export default function() { http.get("http://10.1.2.3/"); }
+					var http = require("k6/http");;
+					exports.default = function() { http.get("http://10.1.2.3/"); }
 				`)
 	require.NoError(t, err)
 
@@ -843,14 +845,14 @@ func TestVUIntegrationBlacklistOption(t *testing.T) {
 
 func TestVUIntegrationBlacklistScript(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-					import http from "k6/http";
+					var http = require("k6/http");;
 
-					export let options = {
+					exports.options = {
 						throw: true,
 						blacklistIPs: ["10.0.0.0/8"],
 					};
 
-					export default function() { http.get("http://10.1.2.3/"); }
+					exports.default = function() { http.get("http://10.1.2.3/"); }
 				`)
 	if !assert.NoError(t, err) {
 		return
@@ -886,12 +888,14 @@ func TestVUIntegrationHosts(t *testing.T) {
 
 	r1, err := getSimpleRunner("/script.js",
 		tb.Replacer.Replace(`
-					import { check, fail } from "k6";
-					import http from "k6/http";
-					export default function() {
-						let res = http.get("http://test.loadimpact.com:HTTPBIN_PORT/");
+					var k6 = require("k6");
+					var check = k6.check;
+					var fail = k6.fail;
+					var http = require("k6/http");;
+					exports.default = function() {
+						var res = http.get("http://test.loadimpact.com:HTTPBIN_PORT/");
 						check(res, {
-							"is correct IP": (r) => r.remote_ip === "127.0.0.1"
+							"is correct IP": function(r) { return r.remote_ip === "127.0.0.1" }
 						}) || fail("failed to override dns");
 					}
 				`))
@@ -972,8 +976,8 @@ func TestVUIntegrationTLSConfig(t *testing.T) {
 		data := data
 		t.Run(name, func(t *testing.T) {
 			r1, err := getSimpleRunner("/script.js", `
-					import http from "k6/http";
-					export default function() { http.get("https://sha256.badssl.com/"); }
+					var http = require("k6/http");;
+					exports.default = function() { http.get("https://sha256.badssl.com/"); }
 				`)
 			if !assert.NoError(t, err) {
 				return
@@ -1013,7 +1017,7 @@ func TestVUIntegrationTLSConfig(t *testing.T) {
 
 func TestVUIntegrationOpenFunctionError(t *testing.T) {
 	r, err := getSimpleRunner("/script.js", `
-			export default function() { open("/tmp/foo") }
+			exports.default = function() { open("/tmp/foo") }
 		`)
 	assert.NoError(t, err)
 
@@ -1032,16 +1036,16 @@ func TestVUIntegrationCookiesReset(t *testing.T) {
 	defer tb.Cleanup()
 
 	r1, err := getSimpleRunner("/script.js", tb.Replacer.Replace(`
-			import http from "k6/http";
-			export default function() {
-				let url = "HTTPBIN_URL";
-				let preRes = http.get(url + "/cookies");
+			var http = require("k6/http");;
+			exports.default = function() {
+				var url = "HTTPBIN_URL";
+				var preRes = http.get(url + "/cookies");
 				if (preRes.status != 200) { throw new Error("wrong status (pre): " + preRes.status); }
 				if (preRes.json().k1 || preRes.json().k2) {
 					throw new Error("cookies persisted: " + preRes.body);
 				}
 
-				let res = http.get(url + "/cookies/set?k2=v2&k1=v1");
+				var res = http.get(url + "/cookies/set?k2=v2&k1=v1");
 				if (res.status != 200) { throw new Error("wrong status: " + res.status) }
 				if (res.json().k1 != "v1" || res.json().k2 != "v2") {
 					throw new Error("wrong cookies: " + res.body);
@@ -1086,11 +1090,11 @@ func TestVUIntegrationCookiesNoReset(t *testing.T) {
 	defer tb.Cleanup()
 
 	r1, err := getSimpleRunner("/script.js", tb.Replacer.Replace(`
-			import http from "k6/http";
-			export default function() {
-				let url = "HTTPBIN_URL";
+			var http = require("k6/http");;
+			exports.default = function() {
+				var url = "HTTPBIN_URL";
 				if (__ITER == 0) {
-					let res = http.get(url + "/cookies/set?k2=v2&k1=v1");
+					var res = http.get(url + "/cookies/set?k2=v2&k1=v1");
 					if (res.status != 200) { throw new Error("wrong status: " + res.status) }
 					if (res.json().k1 != "v1" || res.json().k2 != "v2") {
 						throw new Error("wrong cookies: " + res.body);
@@ -1098,7 +1102,7 @@ func TestVUIntegrationCookiesNoReset(t *testing.T) {
 				}
 
 				if (__ITER == 1) {
-					let res = http.get(url + "/cookies");
+					var res = http.get(url + "/cookies");
 					if (res.status != 200) { throw new Error("wrong status (pre): " + res.status); }
 					if (res.json().k1 != "v1" || res.json().k2 != "v2") {
 						throw new Error("wrong cookies: " + res.body);
@@ -1144,7 +1148,7 @@ func TestVUIntegrationCookiesNoReset(t *testing.T) {
 
 func TestVUIntegrationVUID(t *testing.T) {
 	r1, err := getSimpleRunner("/script.js", `
-			export default function() {
+			exports.default = function() {
 				if (__VU != 1234) { throw new Error("wrong __VU: " + __VU); }
 			}`,
 	)
@@ -1241,8 +1245,8 @@ func TestVUIntegrationClientCerts(t *testing.T) {
 	go func() { _ = srv.Serve(listener) }()
 
 	r1, err := getSimpleRunner("/script.js", fmt.Sprintf(`
-			import http from "k6/http";
-			export default function() { http.get("https://%s")}
+			var http = require("k6/http");;
+			exports.default = function() { http.get("https://%s")}
 		`, listener.Addr().String()))
 	if !assert.NoError(t, err) {
 		return
@@ -1330,10 +1334,12 @@ func TestHTTPRequestInInitContext(t *testing.T) {
 	defer tb.Cleanup()
 
 	_, err := getSimpleRunner("/script.js", tb.Replacer.Replace(`
-					import { check, fail } from "k6";
-					import http from "k6/http";
-					let res = http.get("HTTPBIN_URL/");
-					export default function() {
+					var k6 = require("k6");
+					var check = k6.check;
+					var fail = k6.fail;
+					var http = require("k6/http");;
+					var res = http.get("HTTPBIN_URL/");
+					exports.default = function() {
 						console.log(test);
 					}
 				`))
@@ -1349,42 +1355,42 @@ func TestInitContextForbidden(t *testing.T) {
 	table := [...][3]string{
 		{
 			"http.request",
-			`import http from "k6/http";
-			 let res = http.get("HTTPBIN_URL");
-			 export default function() { console.log("p"); }`,
+			`var http = require("k6/http");;
+			 var res = http.get("HTTPBIN_URL");
+			 exports.default = function() { console.log("p"); }`,
 			k6http.ErrHTTPForbiddenInInitContext.Error(),
 		},
 		{
 			"http.batch",
-			`import http from "k6/http";
-			 let res = http.batch("HTTPBIN_URL/something", "HTTPBIN_URL/else");
-			 export default function() { console.log("p"); }`,
+			`var http = require("k6/http");;
+			 var res = http.batch("HTTPBIN_URL/something", "HTTPBIN_URL/else");
+			 exports.default = function() { console.log("p"); }`,
 			k6http.ErrBatchForbiddenInInitContext.Error(),
 		},
 		{
 			"http.cookieJar",
-			`import http from "k6/http";
-			 let jar = http.cookieJar();
-			 export default function() { console.log("p"); }`,
+			`var http = require("k6/http");;
+			 var jar = http.cookieJar();
+			 exports.default = function() { console.log("p"); }`,
 			k6http.ErrJarForbiddenInInitContext.Error(),
 		},
 		{
 			"check",
-			`import { check } from "k6";
-			 check("test", {'is test': (test) => test == "test"})
-			 export default function() { console.log("p"); }`,
+			`var check = require("k6").check;
+			 check("test", {'is test': function(test) { return test == "test"}})
+			 exports.default = function() { console.log("p"); }`,
 			k6.ErrCheckInInitContext.Error(),
 		},
 		{
 			"group",
-			`import { group } from "k6";
+			`var group = require("k6").group;
 			 group("group1", function () { console.log("group1");})
-			 export default function() { console.log("p"); }`,
+			 exports.default = function() { console.log("p"); }`,
 			k6.ErrGroupInInitContext.Error(),
 		},
 		{
 			"ws",
-			`import ws from "k6/ws";
+			`var ws = require("k6/ws");
 			 var url = "ws://echo.websocket.org";
 			 var params = { "tags": { "my_tag": "hello" } };
 			 var response = ws.connect(url, params, function (socket) {
@@ -1393,15 +1399,15 @@ func TestInitContextForbidden(t *testing.T) {
 			   })
 		   });
 
-			 export default function() { console.log("p"); }`,
+			 exports.default = function() { console.log("p"); }`,
 			ws.ErrWSInInitContext.Error(),
 		},
 		{
 			"metric",
-			`import { Counter } from "k6/metrics";
-			 let counter = Counter("myCounter");
+			`var Counter = require("k6/metrics").Counter;
+			 var counter = Counter("myCounter");
 			 counter.add(1);
-			 export default function() { console.log("p"); }`,
+			 exports.default = function() { console.log("p"); }`,
 			k6metrics.ErrMetricsAddInInitContext.Error(),
 		},
 	}
@@ -1428,12 +1434,12 @@ func TestArchiveRunningIntegrity(t *testing.T) {
 
 	fs := afero.NewMemMapFs()
 	data := tb.Replacer.Replace(`
-			let fput = open("/home/somebody/test.json");
-			export let options = { setupTimeout: "10s", teardownTimeout: "10s" };
-			export function setup() {
+			var fput = open("/home/somebody/test.json");
+			exports.options = { setupTimeout: "10s", teardownTimeout: "10s" };
+			exports.setup = function () {
 				return JSON.parse(fput);
 			}
-			export default function(data) {
+			exports.default = function(data) {
 				if (data != 42) {
 					throw new Error("incorrect answer " + data);
 				}
@@ -1477,9 +1483,8 @@ func TestArchiveNotPanicking(t *testing.T) {
 	fs := afero.NewMemMapFs()
 	require.NoError(t, afero.WriteFile(fs, "/non/existent", []byte(`42`), os.ModePerm))
 	r1, err := getSimpleRunner("/script.js", tb.Replacer.Replace(`
-			let fput = open("/non/existent");
-			export default function(data) {
-			}
+			var fput = open("/non/existent");
+			exports.default = function(data) {}
 		`), fs)
 	require.NoError(t, err)
 
@@ -1497,25 +1502,25 @@ func TestStuffNotPanicking(t *testing.T) {
 	defer tb.Cleanup()
 
 	r, err := getSimpleRunner("/script.js", tb.Replacer.Replace(`
-			import http from "k6/http";
-			import ws from "k6/ws";
-			import { group } from "k6";
-			import { parseHTML } from "k6/html";
-
-			export let options = { iterations: 1, vus: 1, vusMax: 1 };
-
-			export default function() {
-				const doc = parseHTML(http.get("HTTPBIN_URL/html").body);
-
-				let testCases = [
-					() => group(),
-					() => group("test"),
-					() => group("test", "wat"),
-					() => doc.find('p').each(),
-					() => doc.find('p').each("wat"),
-					() => doc.find('p').map(),
-					() => doc.find('p').map("wat"),
-					() => ws.connect("WSBIN_URL/ws-echo"),
+			var http = require("k6/http");
+			var ws = require("k6/ws");
+			var group = require("k6").group;
+			var parseHTML = require("k6/html").parseHTML;
+
+			exports.options = { iterations: 1, vus: 1, vusMax: 1 };
+
+			exports.default = function() {
+				var doc = parseHTML(http.get("HTTPBIN_URL/html").body);
+
+				var testCases = [
+					function() { return group()},
+					function() { return group("test")},
+					function() { return group("test", "wat")},
+					function() { return doc.find('p').each()},
+					function() { return doc.find('p').each("wat")},
+					function() { return doc.find('p').map()},
+					function() { return doc.find('p').map("wat")},
+					function() { return ws.connect("WSBIN_URL/ws-echo")},
 				];
 
 				testCases.forEach(function(fn, idx) {