What a wonderful demo. It feels like you took some of the best parts of kirby levels and made it into a fun game. There's a lot of thought put into the switching mechanic and to make each weapon feel very fun kudos.
I don't have any gripes at the moment other than some weapons are inherently easier to use than others (the axe taking some used to) and it being daunting on some players all the switching and mechanics. There's a lot in there, especially in the upgrades, that may need to be explained.