Great entry, managed to beat it after a few tries!
You mentioned in the comments, that you wanted to make the turn timer speed adjustable. I think a fully turn-based system might also be a good addition, where the guards move every time you make any action - so picking up a card, hacking, or entering another room. Since you cannot be attacked while you're standing still, it wouldn't make a lot of difference gameplay-wise, but could make things snappier. Fully turn-based is supposed to be better for the Neuro integration too.