I am so thrilled that this is your first game!
Congrats for your work!
I need to point out some stuff that might be useful to improve yourself, and that's what game jams are about.
Welp, to start it, we should talk about mechanics. I think there could be a better way of spawning enemies. They just keep coming like crazyyy from the same spots and if I find the spawnpoint I can just keep shooting at it and I won't be in trouble. So, it would be easy to break highscores in this way.
Also, there is a bug, that I get to some level that I will fall through the floor and I can't play anymoer, so I have to close the game and re-open it to be able to play it again.
It is sad that there is no music, it would give more personality to the game.
Anyways, with improvement, gameplay would be cooler. I like that it is a frenetic game and I like the way we aim at the enemies.
Keep on doing it and improving yourself! For a first game (and also considering the time given), you did a nice job!
Congrats!