Thank you too for reviewing my game!
At first I thought letting the player change size by simply pressing a key, but I thought it would be more original to integrate the size shifting into the puzzles. You'd need to devise a route to change into the appropriate size and solve the level, and I wanted to make traps that forced you to change size if you weren't careful. But I also didn't have more time to spend into the level design haha
Though I'll keep your suggestion in case I keep working on it. Thanks!