Easy "It's All in the Mind" trophy
To reach a 500 combo you must beat 500 enemies in the row without any mistakes. This involves kicking each enemy and picking up every bonus from them, including non-score bonuses such as Chi, etc. To do this easier, select Survival mode. Keep restarting it until two easy songs appear (for example, enV songs or any song you are skilled at). Complete both of them perfectly.