Lots of fun, and about the only complaint to be had is just that there's no save feature, meaning you need to beat the game in one sitting, and you can't revisit some content without grinding through everything else first.
Also, a small tweak that could help: Make the Wand charge passively, and let the player move and shoot.
Slimes are the single most annoying enemy in the game, and that's solely because they are fast enough that you can't charge up a shot without getting hit. On top of that, they're so frequent and fast they mostly get you when you're exploring.