Hot Blood High School Dodgeball (TurboGrafx)
CheatingDome.com
Expert mode
Press L, II ten times, Right, Select at the title screen.
Invincibility
Press Up, Down, Up, Up, Right, Down, Left three times, 2, 1 at the title screen.
Unlimited time
Press I three times, II, I, II, I, I, II, I at the title screen.