Probably doesn't hold up anymore, but no one really talks about "Kingdom ConquestCrusade". It's like a really tight minimalist version of the combined live action melee and big battle strategy of the Dynasty Warriors series - compressed to fit on a classic Gameboy.
It takes a minute to figure out the combat, and map contains, and which characters are strong against which. After that, it's a great little time passer with a bit of strategy.