I've remembered good old csgo aim_botz days and stood in the middle, rotating the mouse and clicking on the flowers tips (I assume this is their vulnerable spot?).
The game looks nice and polished, it's remarkable you've managed to make it in such short time. I've liked the art (graphics, models, the music too) a lot. The overall gameplay (shooting, moving) was also on point. I wasn't able to move to the right, because my d button is broken. I've got 76 points as a personal record tho.
We've got a somewhat similar idea too. Even though our game is in 2d and its style is completely different, i think what your game needs too is more variety, as some other commenter said. You might have added enemies of different size, or collectable gun boosters.
Also, I personally would prefer, if the monsters would make less damage in one hit but had slightly more health, punched you faster and you could collect hp boosters. However, it's my personal preference that you may not consider.
At the end, i liked the game and admire you for getting it done in just 3 days(!). Hope to see your future games to