I really enjoyed the game, and it felt kind of like Enter the Gungeon to me. Also, I think you should consider having a patron account to help with developing the game.
One thing that I think would be kind of cool, is that when a player finishes the campaign, they could unlock different game-modes. Such as an endless mode with randomly generated levels, monsters and items. Or an all new difficulty you could get from beating it on hard.
Sometimes it can feel a fairly slow.. I think that if you made the AI for the enemies "smarter", and added a few more attack animations, it would make the game feel a bit faster. Also, if you added different enemy types that look different, sound different, and have seperate attack animations would help the game not feel as repetetive.
P.S. - Making it so that the spawn locations of enemies, type of enemies, and drop rate of items is partially random for each level, could help with replay-ability.