Oddly, I think the Gamma Bomb is more dangerous now than when it came out. Dials are generally shorter these days, so that damage that doesn't require an attack roll goes farther than it used to in a lot of cases.

One of the funniest/silliest things I've done with the Gamma Bomb was run a gang of Flatman figures with TabApp Iron Man. I waited slightly outside of the Bomb's blast zone and charged in as closely as I could to right before it went off. If my opponent came to me, I'd bury him in Flatmen to keep him in the blast zone. I outwitted as many damage reducers as I could between Flatmen and Iron Man so the bomb would have maximum effect, even if it did blow up the Flatman brigade and damage (in one case KO) Iron Man. Results were mixed, but generally pretty damn funny. This was also a little easier because Flatmen could carry each other with that Giant Reach at the time. Still, good times.