This game is a cel-shaded Super Smash Brothers style game. There are a few game modes to choose from.
1. DEMONIC HORROR MODE: Select your character and battle it out in every stage against 3 random opponents each battle.
2. VERSUS MODE: First, decide if the mamono fight solo, or in teams. Next, decide how many will be in the brawl, then select your characters, arena, and even battle options and get fighting!
3. STORY MODE: Choose between either Gash's Story, Tio's Story, Kyanchome's Story, or Umagon's Story to play in.
Source: Wikipedia, Konjiki no Gash Bell!! Go! Go! Mamono Fight!! , available under the CC-BY-SA License.