Wow really good try dude! The enemies are definitely not supposed to be invisible - that is a confirmed bug and a clear shader issue. Also, you are not supposed to be able to break that door with the axe, the key is hidden elsewhere. However I like your thinking and will probably let that be as is.
What version of windows are you running and what are your system specs? May help me diagnose. Needs a new installer because it requires direct x 9 as well - if that isnt installed that may what's causing the issue.
As far as the power puzzle, the wires are connected by pressing keyboard keys in order(you may have the manuel equipped while doing this). Like so: a -> b, b -> c, c -> a would be entered like this: a,b,b,c,c,a if that makes sense. You dont need to be looking at them or click them, punching keys is sufficient my friend.
Dont forget there is a save function that will be improved later, but saving often will make beating the game a lot easier :)
Thanks so much for playing and for the valuable feedback! Liked and subscribed 👍 Let me know about those system specs so I can work on the shader issue - thanks