Lunar shadow was a legendary ultimate fighting school, but its last descendant lived 80 years ago.
Kusakabe Aoma is a bouncer of the street gang group in the city called Crown City. But he wants to get to know his true self. One day he arrives to the usual place, but instead of smiles of other members all he sees is a sea of blood.

[From vndbreview]

Our guy regain control in a room full of dead bodies. It seems he killed them all to protect the only other live person, a girl who became speechless due to shock. He is told to join a fighting tournament as a test. There, he met some friends that might help him regain lost memory. There seem to be a secret oraganization that is interested in him. Anyway, between story and H scene, you have to help him fight almost arcade style. During fights, you issue commands using the mouse in a 9 block square. With that, you can move, block, use AP to do attacks or charge up FP, neat. If you finish this game, you can also battle using/with any of the game chars that fight.

[From Li's Fun House]