Overall a quirky and fun take on the classic shooter influences that you identified (COD, Vampire Survivors etc).
When Vampire Survivors was mentioned, my mind immediately went to scope creep -- a game like VS tends to be content-heavy with lots of variation in upgrade types, and there are plenty of challenges with making a game of this genre. It wasn't completely clear which aspects of VS would/would not be be in the prototype. The smart option would be to ignoring/cutting back on some of the trickeir asepcts such as the uprgrade system and the reliance on having a very large number of enemies (since this leads to difficulties in terms of framerate).