Hyper mode:
Press A(9) at the title screen.

Finishing move:
Press D(3) when your opponent's life bar is less than 2.5 life balls in length.

Transform into Spike:
To turn into "Spike" the scorpion, defeat The Jester. This actually is done twice, since he has two lifebars. After he is defeated, The Jester will sulk and say "OK, your wish is granted". Your character will transform turn into Spike the scorpion as The Jester flies away. The game will continue with matches without Superbosses such as Spike. Note: It is possible that you have to choose Bruiser as a fighter in order to transform into Spike.