I decided to try this game because I'm a casual enjoyed of shooters. By this I mean I can usually beat them, but I don't try to 1CC them or anything.
In my opinion movement needs to be a little bit slower at the start so it's easier to move short distances. Placing the character near the edges of the screen seems to be a formula for getting stuck unable to move for several seconds.
Difficulty is really low so it's not really needed, but the expectation is that these games have really precise movement. On a similar note, I think the slow down skill may not slow down your character as much as the enemies? I'm not completely sure.
The settings menu is under construction so I would like to suggest an option to keep the hitbox permanently visible and the ability to either remap controls or some alternative controls schemes. I personally like having all of the possible actions as a single row of buttons on the keyboard. Something like ZXCV with the arrows or HJKL with WASD tends to work fine for me.
Finally, I think your character sprites are detailed and well animated and you deserved praise for that. Good job.