2 things would make it easier to plan -- a "time until next wave" counter, and some kind scouting ability so you can see what is coming. Either (or both) of these could be incorporated into a skill, either unit attached or not.
@ souicia No, its an old school dungeon crawl where you need both strategy and tactics. Free health/power refills are a modern thing, and make a game much easier/simpler, which is not always a good thing.
The buy & improve option sounds good -- perhaps an option in stores? Only works if what you need is sold there? I know I spend a fair amount of time in a store, every so often, purchasing craft materials and improving gear. Or, if the next series really wants to go RPG a blacksmith's shop for improving weapons & tailor's shop for improving gear, plus perhaps a alchemist for improving flair, which would have this option for a small fee?
Great game! It would be nice to have some ability to see what foes are in a particular battle before entering it, so equipment can be changed before the fight. I often don't use a specialized weapon or piece of equipment because it's not worth losing a turn to change over -- I can kill the sucker anyways, in a couple turns.
 "Royal Warfare"){kind=icon}
 "Monsters' Den Chronicles"){kind=icon}
 "Super Villainy"){kind=icon}
 "Epic Battle Fantasy 4"){kind=icon}