Marvel Ultimate Alliance
58 Achievements
1,250
Widowmaker
Threw 500 enemies off a ledge. Details for this achievement will be revealed once unlocked
30
How to unlock the Widowmaker achievement in Marvel Ultimate Alliance - Definitive Guide
If you would like to get this out of the way while you play the story, there is a perfect spot during the Mephisto levels. When you get to the section where you need to complete the five trials to save Ghost Rider, you will come to a trial where you need to throw imps into the lava in the middle. The imps will spawn infinitely here (but only during the story), so you can kill your AI characters so they don't get in the way and then just throw the imps off the side forever. Using Hulk is nice for this as it is easier to direct the throws. Invisible Woman and Dr. Strange have nice throws as well with their skills (Telekinesis and Levitate, respectively).
If you have already completed the story and need additional kills, you can use either the extraction point Sepulcher which will have a ton of enemies to throw off the side after you cross the bridge, or any of the numerous Asgard sim missions (such as Piledriver), which has a nice spot on the big bridge toward the end. The Asgard mission has infinite spawns, while Sepulcher has dozens of enemies to spawn, but will eventually run out. If you run out of enemies, you can extract to six other zones and return, and the enemies will be back.