Before rmxp I saw a couple different evented battle systems in rm2k that were crazy complex. Things like character turns, stats, battle damage, menu and animations were all done with pictures and events. If you were to look inside just one event you'd see 10 pages of conditional branches and variables for whatever mechanic that event was used for.
All your system does is take turns hitting each other with a preset number until one of you hits zero. You could at least have a success rate of whether or not an attack misses. Or something like a critical hit. I tried, but I couldn't died even if I wanted too. You could probably turn it into a rock paper scissors game. Attack trumps magic, magic trumps guard, guard trumps attack.
You'll need some kind of hub made with pictures or events that shows health and sp at least.