Hi! In the past 3 months i did add an upgrade system and progressiveley harder enemies each night, here's the demo if you have the time:
https://naardev.itch.io/ice-fighter-demo
and the steam page:
https://store.steampowered.com/app/2648300/Ice_fighter/