Introduction[]
Isn't That Cheating? is an Achievement in Run 3.
Suggested Characters: 
Gameplay[]
This achievement may take some time to figure out how to do if using a character besides the suggested ones, but after you figure it out, it is very easy.
To get the achievement, when you start the level, you have to move to the edge of any of the 8 sides of the tunnel. One of the sides will always be there for you to stand on for most of the edges, so you will complete the achievement.
Any character will work, but a cheap and fast way is the Skater, as he is probably your fastest way of getting this achievement, since his high speed lets him glide past those alternating gaps with more ease than other characters. You won't unlock Skater until Level 10, so play through level 10, then go back to earn this achievement.
The Pastafarian on the other hand makes this so much easier as her light bridge will not require you to go to the edge of the tunnel and will instead just block the gaps in the level. The Bunny can also earn the achievement easily, because it can jump without you pressing anything, which is very useful.