I really like this, it has tons of great potential. Dodging bullets is really fun and enjoyable, likely because of the slow moving projectiles that everyone fires. The flying guys in particular I really like. They felt like a really interesting challenge that was genuinely fun to beat. The placement of enemies was pretty good as well, some of the encounters, like the flying enemy on the last part by the elevator, and various parts where you hide enemies where the player isn't looking were pretty cool. There's only two weapon pickups, and five different weapon combinations, this part of the game feels like it has the most potential, so I hope you think long and hard about each new weapon you add in as this project progresses.
There are only two enemies in this short demo, and the main difference between the two is that one can fly, and the other can't. Other than that, both of them fire slow-moving projectiles at you, I feel like if one thing besides the weapons are going to make this game shine, it's gonna be the enemies. I suggest you have at least one or two enemies that deal little damage, but perhaps use hitscan weapons, this forces the player to think about the combat situation they are currently in a lot more, since they now have to figure out which enemies are more dangerous than others, and which ones they should kill first. Also, having enemies that might initially be on the ground, but maybe start flying and swapping tactic to really try and get behind you when they're on low health would also be very interesting to see.
Nice progress, good luck with the game going forward.