I think is unintended, but you can gain EXP from secrets, and there are secrets that are activated from switches, when that is the case, you can press the switch as many times as you like and you will be adding exp as much as you like.

The game need a tweek in the dificulty department, the game is quite easy, and there should be more dificults to choose from.

Not a fan of losing everything after dead tho.