There was definitely some craziness with the gravity flipping which took a lot of getting used to. Once I mostly did tho it was interesting, a bit weird to jump, but interesting. The weapon types definitely took me off guard because I got some very lucky rolls or something where I almost always had the same weapon for a bit, and then it randomly switched to a shotgun and I was very confused.
Other than that though I was mostly just confused by the enemy types since they didn't seem to be very distinct, except in their visuals. Since I saw some that were melee one time be ranged other times etc.. It was definitely weird and got me quite confused on how to deal with each of them separately.
Overall though, an interesting little arcade game, I do think more of an indication on when things were changing would be nice. Otherwise, pretty good.