Sonic Generations

This achievement is notoriously glitched. If it does not trigger after 100 kills(around Sky Sanctuary), it will not trigger at all.

If this happens, simply create new save on a different storage device like the Cloud Storage(or USB drive). Play game from start and you should get achievement after 100 kills. Should take 20 minutes tops.

This is cumulative across every level and every life. Unless you've been avoiding enemies for some reason, you should easily have this before you finish Sky Sacntuary.

WARNING: Many of the achievements are glitched in Sonic Generations. If it doesn't pop for you when it should, you may have to get it again on a new save file on a new save device like a flash drive or something. This is the only way I've heard of. And don't complain about it here, I had it happen to me with the achievement for collecting EVERYTHING.

I thought I would add this just in case others are having some issues with getting this to pop. I had this achievement glitch on me, and you can see that this was the very last achievement I got on this game to complete it 100%.

I completed the game first - all but this achievement. Then....

What I did was start a new save file on a flash drive. The game requires you to play Act 1 and Act 2 of Green Hill before it opens up. I died on Act 2 one time (I jumped over the bumper and fell to my death). Then I went back and played Act 1 until I had more than 100 kills - the achievement still did not pop.

I then deleted the save file on the flash drive and started another new game, new save on that same flash drive. This time I played Act 1 and Act 2 of Green Hill and did not die at all. I then played Act 1 until I had 100 kills, the achievement popped this time. In fact, the achievement popped in the middle of the level. I did not even have to finish the level for it to count.

So it appears that dying before you get the 100 kills is a problem. It may be THE problem, but I don't know for sure. Maybe it is not just dying but dying by falling to your death. I am not sure. But if you are having this problem, if you start on a new save and don't die, you should get this achievement.

I had read the comment by LitaOsiris on another solution and how they just played Act 1 and Act 2 until they got the achievement as well. So I did the same thing and can confirm that it works. Of course, I died on my first attempt.