Hey ueih!
First of all just wanna say your game is awesome! I'm new at game dev as well learning how to create my first game now but I will do my best to give some feedback. Of course these are just my opinions too! Overall I really like it!
I played for about 20 - 30 minutes and the high score I got was 79. I think that I could get higher if I keep playing and improving.
So at first I didn't realize that the player can hold the 'w' key to aim up, it doesn't seem to be in your list of controls on the game page? The game was very difficult at first until I figured that out. Using the w key to aim up made the game easier but not in a bad way its nice to have good control over the character instead of feeling like you're fighting with the controls to get it to do what you want it to do. The key setup I liked the most was A/D to move, K to shoot and L to dash. Those in combination with 'w' to aim up was the most comfortable for me to not have to keep repositioning my hands while playing.
I encountered 3 different enemies the purple ground ones, the floating lightning bolt firing eyeballs and the small little floaty guys who self destruct. As I played more I felt like the most difficult enemies to deal with were the floating lightning bolt eye guys the self destructors and purple monsters were a bit easier to navigate around as using a dash made it pretty easy to escape them or pass right through them while avoiding their attacks. Of course that's not a bad thing some enemies are supposed to be easier than others I'm just saying this to give an example of where the players mindset might be at when playing this game.
My strategy was mostly to dash under the eye guys and deal with them as quickly as possible and then mop up the rest and if there were too many I would try to dash my way to the far sides of the map getting as many self destructors along the way as possible to thin out the numbers then dashing back in to get the eyes. Of course the problem with this ended up being that hanging out by the far right and left sides of the map made me a target for monsters off screen to hit me. Just my 2 cents but its probably not good to let the enemies attack the player from off the screen in this type of game. If you cant see what you're getting hit by you cant really prepare and the only solution ends up being camping in the middle of the map which cuts down on the total area that the player will try to stand in. Once the score gets high, running too far to the sides means its highly likely you'll get hit by a lightning bolt from off screen.
I thought the sound effects were nice the only one that seemed off to me was the footsteps they just felt a bit slow to me compared with the movement animation of the player.
When firing upward, the player only changed the animation to look like they are aiming upward when the firing key is pressed instead of the 'up' or 'w' key which was a bit more awkward creating a quick stuttering animation when firing upward.
A couple more minor things that could help it be more fun would be a cooldown timer for the dash to visually show when its ready again. A cooldown timer would also be nice for the bullet powerups too.
Overall I think you did a great job it was a lot of fun to play thanks for sharing!