Hi Zaeran!
I am working on a GUI.. I literally just learned how to use Pictures in lieu of events about 2 weeks ago. I've gotta say this has really unlocked a lot of possibilities! I want to have boss and player health meters. I'm not a fan of the message box for battle commands either, casting spells from scroll is painful and so I'll be seeking to revamp that menu system entirely, probably with pictures.
I'm releasing an update at the end of this month, and that should include these two boss battles... but in the actual dungeons instead of on this testing field.
I welcome any suggestions you have Zaeran!