One player if its a action adventure , the format would fused Ninja Gaiden + DMC .
Guyver I starting off , & Guyver III playable later like level 3, you'd have to fight him like a test or something. Guyver II has to be defeated a certain way, to play as him. which would help with characters like Guyver II & Guyver Apton.. "limited time play". ( Capcom vs's titles, where while the characters are rotated to fight, the one not fighting can heal a bit.)
Guyver IIF, Murakami, & Guyver 0 would be "LTP"secret playable characters in the sequel.
The other would be a few fighting games
1. 2D fighter KOF/Guilty Gear style
2. A Dead or Alive/Virtual Fighter (VF, yeah i said it!) Type.