: Equip Life Leech + Steel Skin . This allows you to mitigate damage with a metal exterior while simultaneously refilling your health bar by landing hits.
Since you're looking for a useful feature for on XBLA, the most impactful addition would be a Psi-Amp Synergy Guide . Girl Fight XBLA - Xbox 360 [Arcade]
In Girl Fight , you can equip two psionic abilities (Psi-Amps) at a time. A "useful feature" for a player today would be a synergy-based loadout manager. : Equip Life Leech + Steel Skin