Publisher: Haruno Games
This is a sliding block puzzle game where the object is to line up three or more gems of the same type, making heart gems appear which do damage to the opponent when you click them. There are eight girls to choose from, who expose themselves if you get their HP down to zero. It sounds like it might be challenging, but it isn't at all. Once you learn how to play the game, it's a breeze.
This game was formerly available from DLsite English, but has since been removed.