Theres some wonkyness on the right Side going on like the Walls are changing Geometry when moving out of the Screen at the Bottom or something.
Bullets also stack up rather weirdly, they don't feel like individual Bullets or a Sea of them you're wading through, but like a moving Polygonal Shape. With that small Jump and the Bullets constantly blocking you, jumping feels very unsatisfying and not very useful.
Biggest Issue I had tho, was that whenever I started shooting for a while, or occassionally in between the Minigun would lock on to the top left Corner with a blue Circle and I couldn't aim anymore, making it pretty much impossible to kill most Enemies, unless they just happened to be right in that Corner.