Hello, yeah I had a few people tell me that as well when playing as they were testing :P So here are some answers :D
1. Your assumption that there is more to be done/find in the computer area is correct :)
2. So I cant give away too much here, except, admiring the artwork is important to finding the maze, time is also important, also the code. One important hint to save you time, once you admire all the paintings except the two unavailable ones, check the black and white room for something that can save you time from doing this again, I know the admiration part is tedious, so there is something that can help once you do it one time fully.
3. This one is obtuse, think of a calendar and add a century to it... what date would that Tuesday fall on?
4. Yes 100% Construct will let you shimmy through walls in some spots, I never really 100% found a way to stop this :P but yeah those areas where it can be done are just bugs.
5. So if you have a twitter feel free to message me on there directly, or if there is a way on here and I can help a bit more, I don't want to give away too much over these posts.