Spider-Man: Edge of Time

I got this in Act 3 on the part where the information is being downloaded after moving all the data carts into position. A challenge will pop up where you have to get a 30 combo streak in 30 seconds.

Many, many enemies will appear. Just keep button mashing X and Y and change direction with the analog stick so you don't kill all of them. I did this on normal, which is probably your best bet since the enemies will stay alive longer allowing for more time to get a combo.

I ended up getting a 191 combo streak so you shouldn't have any trouble getting 100.

Thanks to Achievaholics,

I found this video on Youtube. This video showed me one good way to do this achievement, with no troubles, on the level The imperfect storm.

for this just find a area with lots of enemies and build up the combo by hitting enemy after enemy and mix up the buttons you use and use different attacks