Hello there,
First I would like to thank you for taking the time and playing my game. It means a lot to me!
To answer your questions - I used Unity to create the game (I use it because I like c# and some of my favourite devs use it too so this way I can get my motivation from them).
For the door part. Can you specify your problem because I am trying to replicate it based on the info you've given me but I cannot find myself not opening the door? Can you say what did you do, which level was it. So I can try and replicate it and possibly fix it.
Thank you for the comment,
Cheers!