So… Uh…
When you first play as c4f3…
If you go in the back door of the robotics lab(?)…
The camera shakes before loading the next map and there's a 'thud' sound…
And then the interior map loads and the game locks up…
Oh, that's interesting. You've found a glitch that's related to the janky way the multi-screen scenes work. The pathfinding moves you into a scroll trigger, which causes a signal to fire that makes the scene transition happen, but controls never get re-enabled because the player character never arrives at the co-ordinates the game is expecting.
I've implemented a quick workaround in the web version, pending a proper fix, which should make it harder to get into that situation. Normally you can get out of this sort of thing by restarting the game and reloading the autosave, but obviously that's not always an option. Certainly not the intended experience.
Sorry for the inconvenience and thanks for the bug report!