I hope this doesn't get burried in here
Very good game and generation of the map but i have a few suggestions
New game+ doesn't really change much, maybe try replacing the alchemist with some sort of leveling altar
all enemies exept ones that are spawned(small mushrooms and big ones spawned by the boss) give a certain amount of EXP based on the HP and difficulty of the enemy
to go by zephirith's #3 idea you could limit the amount of levels gained by whatever armor and sword you have, and again, getting new equipment has a level requierment having both the last sword and armor allows for endless levels
the leveling altar can be either just increasing certain stats or a whole skill tree witch would go very nicely with the expasion of the game, this would even unlock new abilities like a dash
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