Thanks for taking the time to try out the demo!
-I have a love/hate relationship with my camera. It will eventually rotate with the player's forward direction as well as allowing you to orbit freely.
-This is a problem with the arrow triggers being too thin. I just fixed it, so thank you for pointing that out.
-Eventually, you'll be able to punch the levers, hit them with a blunt object, or push/pull them in first person.
-Thank you for pointing this out as well, I've gotten so used to it that it doesn't bother me anymore, but definitely needs to be addressed.
-I'll have to figure this one out because I've yet to encounter this bug. I do know that if you pick up a weapon, quit, reload, and try to equip it, nothing will happen. The fix is to open the inventory and equip it again. There's a boolean value that isn't being set to false OnDisable for some reason.
-A tutorial scene is being worked on, I just flat out didn't finish, so I disabled it. I'll add some subtle hints for the puzzles too, so the player isn't trying to guess what to do every single time. And regarding holding the button down, I definitely dropped the ball for not including that in the game page. I've updated the controls section a bit and added a few hints to guide people along should they get stuck.
Again, thank you for trying my demo and leaving such great feedback! I'll be trying your demo out as soon as you update it tonight.