Really cool that you created everything yourself! You got the core gameplay implemented well and there's a fun risks/reward system with a good variety of powerups. Hope that you could further expand on this with more enemies, different weapons/items!
Some suggestions and possible things you could add:
1. Give the player a strafing movement instead, by having the position of the mouse control the direction of attack. It's a little awkward right now because the player has to turn around everytime they want to attack.
2. Give a little feedback when the player or enemy is damaged. Something like an audio cue could work, or a bit of knockback would be even better.