Improvements on the end game would be a good start! I feel like fighting bosses to obtain the most powerful armor and weapons doesn't make the game enjoyable. After you obtain the items, their usefulness is very limited because you've already killed the most powerful bosses in the game. Other than that, improvements on various things. Remove locked chests from floating isles. I see no reason to make chests in floating islands locked. By the time you are in the point of the game where you could unlock them, the items they give are not useful to you. Make the underworld more interesting. No, I don't mean more bosses, I mean.. More variety of things. Less frustrating. Steam achievements for doing things difficult. Beating the game in Copper Armor? Why not? Fix the buff system. Allow for unlimited number of buffs. The amount of buffs or debuffs. Fix Broken armor and weakness so it doesn't last 5 minutes.