I can try to take a look at sizing options. Were you trying on mobile, or any particular display? The sizing has felt fine to me on my desktop but I haven't really tried other devices or display aspects. I think enabling full screen is just an option I can turn on somewhere, I can see about enabling it.
The second battle still has some placeholder text, and might deserve a bit more instruction due to the changes from the first battle. The intention is to have different text that you have to interpret what that means her stance is, but the placeholders are just "attack 1", "attack 2" and so on at the moment. So that text just means she is "attacking" and that there isn't a real blurb for it yet. The red 8 is still the attack value displaying like in the first combat (so you won't really have to interpret her attacking-stance dialogue, since that's present, but it could be relevant for distinguishing the other two).
Edit: Oh boy, full screen does not work well. I think I'd need to figure out how to make the game dynamically resize. As is, you just wind up with the same size game, but in the corner of the screen and a few UI elements misplaced.