Well done! it's impressive that you managed to code the game, make art and music all by yourself... in 3 days.
As already said by Ruby controls are cleverly designed so the player is forced to choose between fighting + moving or moving + recharging without imposing any artificial restrictions.
I like the variety of enemies that behave differently from each other.
Here's some feedback:
1. It's hard to differentiate background layer from foreground layer, maybe adding dim to the background layer will make it a bit more readable
2. It's not possible for me to dodge the enemy attacks because i don't know when they will attack, telegraphing enemy attacks will improve the combat significantly.