I like the game. However there are a lot of things i think could be better. I will be listing some Pros and Cons allong with some suggestions.
Pros
I think the Weapons feel good to fire and making all of them piercing makes it rewarding to line up enemies to blast them all at once.
You can only carry 2 weapons at once which means you can have very varied builds (this would be better with more uniqe weapons.)
Cons
The overall pace of the game feels a little slow but that might be just preference
You have to kill all enemies before the next wave starts which can make it annoying as you have to run around the map trying to fing them (Maybe consider making them despawn if there are only a few left and they are off screen)
All the weapons are pretty similar which makes me not want to upgrade past the 3rd weapon
It would be nice if the current task was somewhere on screen
The grenades are really hard to use well as they take a long time to detonate
also tiny bug i found: when you change what device is the audio out without restarting the audio doesnt work. Is really irrelevant tho.
I would also consider scrapping the thing where you can buy ammo because you get so many of the all ammo filling items.
I also had a hard time finding the next objective which was made worse by the quickly disappearing objective message.
Overall i think the game is pretty fun but maybe a little slow for me. I think the game would profit greatly if there were more varied weapons and enemies. The Weapons feel nice to use and the piercing creates a rewarding game mechanic however this does not make the overall boring weapons more fun to use.