[HL2] Barney gets stuck in the door at the start of half life 2 if you block the door from opening.

[Marktherobot]

if you block the door before Barney opens the door he will either get stuck, or walk through the door and then walk away.
either way this soft locks the game, it's very easy to do, and can even happen if you lightly touch the door while its opening.
a simple fix would be for the door to constantly try to open, or for the sequence to force Gordon back abit.