Some of my favourite games have had the ability to level up limitlessly and alter your difficulty (Disgaea, Rogue Legacy, Borderlands 2) and I think it would be a good fit for arcade mode. Having the ability to toggle them on and off (or adjust the enemy difficulty up and down) would be nice if you wanted to play with a new person but not feel overpowered compared to them. It would fit the name of the game, an extra 1% health (or whatever) per level doesn't seem like it would be game-breaking, and most importantly it would give a feeling of constant progression and reward in arcade mode. I imagine it would be like an arcade mode pet (maybe don't have it follow you since arena maps are small and the pets could clutter it up visually): Health, Mana, Damage, Crit, and Speed could use points to level up instead of the single player drops. Enemy difficulty (With increased exp / drops / points?) would be 1.25x all enemy stats first and increasing to 1.5x, 1.75x, 2x etc. Maybe put this on a different NPC. Both of these systems seem to be in the game already (Pet permanent stat increase and the same monsters having stronger stats in later maps), it would just be nice to have them in arcade mode. Thanks for reading.