I'm just gonna list things and add on over time.
1. Remove background inputs.
Seriously, this is stupid. When you're playing Crusade, you better not try minimizing it to do things that involve typing. The game doesn't act like you minimized it. For example, I use WASD for moving, so if I were to open Google Chrome and search something, every time I press one of those keys, I would move in game. Please fix this, it's annoying.
2. Fix the jump heights.
In any smash game, there are two heights for your jump, short and normal. In crusade, as soon as you let go of the jump button, you fall. This makes things inconsistent.
3. Add some sprites for moves being used in the air.
Examples: Ryu's, Fox's, and Megaman's neutral specials. They use the same sprite of them standing still when they use these moves in the air. This looks extremely stupid.