I've run into a roadblock in chapter 2. I don't know if I'm stupid or this is a glitch but key A which you get to open the doors to get the key card for the adjacent section. I assume it is also for the door labelled 'a' in the next section to get what I assume is the small key. But key A doesn't work on that door and all it tells me is "Closed. You see a "a" letter on the lock" with key a in my inventory. I don't know if there is supposed to be another key a somewhere or if this is just a very unfortunate glitch. I genuinely enjoy playing the game but this just leaves a sour taste in my mouth. It's just annoying really.