A recent
official article on terrain powers--that is, pre-built mechanics for cool environmental tricks like swinging on chandeliers or dumping vats of boiling oil--offers sort of a tier system of non-damage effects which might be useful in developing new powers.
Tier 1• additional damage type (meaning the attack has a better chance of bypassing a resistiance or triggering a vulnerability)
• shift one square
Tier 2• deafen
• gain concealment and/or cover
• knock prone
• ongoing damage
• shift multiple squares
• push, pull, or slide enemy up to 4 squares
Tier 3• -2 to a defense
• gain combat advantage
• mark (that is, -2 to attacks against all targets but the user of the power)
Tier 4• blind
• daze
• immobilize
• restrain
• weaken
Tier 5• dominate
• petrify
• stun
Now, I'm not
sure that all these necessarily have the same potence in GW as in D&D, and the list certainly doesn't cover all the effects a Gamma World power can include (notably, there's no mention of healing effects), but it's a good start. Between this list, Sly Flourish's excellent cheat sheet, and simply eyeballing the existing powers in the book, you ought to be able to come up with some stuff.
I don't know of any official guidelines for area effects, but I did notice that, in her very awesome
Weapon Shoppe, Oraibi balances blast and burst weapons against regular guns of the same type by reducing their accuracy bonus by 2 points and average base damage by about a quarter (for light weapons) or a third (for heavy weapons). (Oraibi, if this is based on any official math or guidelines, I'd really like to know about them.)
Finally, remember that game balance is
not a major concern in Gamma World--not compared to D&D, anyway--so feel free to do cool stuff without worrying too much.
