Walkthroughs for custom maps.

("Ray of Light")

Is this map playable without glitches during battles, or does it require using some tricky mechanics in combat?

Based on what I've played so far (seems like about half, although it appears to be the easier half), the author isn't exploiting any glitches, and everything is based on standard rules. I defeated all the enemies and monsters I encountered using standard methods as well. However, in the battle with Overlord Hex, you need to figure out how to act; otherwise, you won't win. You need to stay put and not engage until the enemy has used up all its mana.
Also, you need to pay close attention to your surroundings, as many useful things are hidden.