Here's my feedback, hope it helps :)
- You shouldn't make players use space bar to confirm their choice in the menu, you should either go all in with keys or all in with mouse controls for the menu.
- Music is a bit weird and kinda irritating
- Font is little hard to read and How to Play screen is a bit too confusing in general, especially given that that's the only way to figure out how to play. Maybe add controls on the actual page, together with rules and maybe even some screenshots that actually show how to play with some text prompts.
- Gameplay is a bit too buggy I feel, although I think I managed to figure out what was intended.
- Units move to the side when I send them into fight which I think is a bug, if it's not, it doesn't really make sense to me.
- I think you should've made it so that dice rolls when you press the key. I don't think that timing mechanic doesn't really work in this case.
- Also, I think that using some more basic shapes for visuals would have worked better for this game. Current graphics seem like they are weirdly scaled.
All in all, I liked the idea but I think other issues really dragged it down.