This was so much fun. I've always loved achievements in games, and didn't even consider there might be games in this Jam with them. This is one of the most fun games in the Jam I've played do far.
My only issue is with the manner in which the difficultly ramps. It seems it's built to "punish" you for doing well rather than rewarding you. If you start hitting and killing things too quickly, the game gives you more enemies and you get overwhelmed. At least that's how it felt.
On the other side, that's really only until you you reach god-mode where you can stand anywhere and just kill all the things and have 1000's of coins and can't die unless you want to. I probably spent longer than is healthy at that point in the game... but darn it I feel like I earned it.