Spider-Man Web of Shadows
45 Achievements
1,000
Xbox 360
Defeat 500 Enemies
500 Enemies defeated
35
How to unlock the Defeat 500 Enemies achievement in Spider-Man Web of Shadows - Definitive Guide
The easiest way (For Me) to obtain this achievement was to defeat the white symbiotes that appear later in the game, they take one hit to kill and there are large numbers walking around the streets.
i actually got this while running around kicking and throwing cars. i checked the solution for getting 1000 kills and he also suggest flipping cars as an alternative way to reach that goal. sometimes it's fun to do if you need a break from searching for spiders.