Features that should be in every game.

[retrolinkx]

I also think that some games should have a "Dynamic Difficulty" in which as you get better at the game the game itself gets harder, and as you become worse the game itself becomes easier.

God Hand did this very well which meant that you were always challenged in interesting ways and had to fight using skill instead of easily beating your enemies because the difficulty was too low, or having to fight different types of enemies that do new things that you're not prepared for if you didn't have harder fighters to fight.