Ya know, seeing this game (and the other one, I think its Invulnerable?), I can't help but feel there's missed potential here.
Wouldn't it be more fun to play an AU where Mark doesn't get powers/dies/is kidnapped/rejects his father and Omni-Man is the protagonist? Run around, at first in secret trying to create a viable heir, 'defending' Earth and growing in power. Slowly over time, Cecil would uncover what you are up to, leading to more overt moves. You could even have a choice based game. Nolan's redemption arc, or embrace your natural supremacy and take your rightful harem and challenge the Emperor himself.
Playing as Mark is... kinda lame.