Easiest game I've played by a country mile. Didn't die once, had no problems with any of the bosses and none of the enemies are more than a mild hindrance. Completed all achievements bar one in one playthrough (not counting the 'finish with x character' ones). Just way too easy. May have made it a bit easier on myself by not upgrading weapons and going for the coin boost upgrades first but can't see it making much difference at all, the game could probably be finished without buying a single upgrade :/
 "Winter rush"){kind=icon}
 "Random Heroes"){kind=icon}