Awe I've just started I want a bit more! Jokes aside, this is quite sweet! I love the fact that you take time to put in in-game instructions, as I always think being able to play the game without much or any reading at all is a big plus. I would suggest don't worry about optimisation for the time being, most game engines will be handling themselves fine. There's a saying that goes "Premature optimisation is the root of all evil, 99% of the time". Just make a product that works and refactor when the project increases in size.
For a little suggestion I would say a pointer to the next collectable will be nice, just to let the player know there is something in the room to collect, and to ease the frustration for getting lost in a big level. You can get away with making the level as complex as you want too.
Anyway, well done on you first jam and looking forward to your next one!