I like the combo system, but a few suggestions:
1. Add sounds and perhaps even some music! It improves your game a lot!
2. Make it so you can attack and move at the same time, or add a little dash when you attack.
3. Keep a consistent artstyle. Like, choose either simple or pixel art.
4. Use a different font than arial.
I hope the feedback helped you, it would be nice if you could check out my submission too. :)