| It's just so frustrating that I have to start over every time I fall.
This achievement is rather difficult and is considered quite hard. Due to its hard difficulty, the number of power cells is higher than most achievements. Infinite Mode level achievements are not affected by this and they still keep their 25-75 power cell rewards.
Straight to the End is an achievement in Run 3.
The Skater is one of the best choices because of his jumps. He can jump far enough to land on the rings of normal tiles. If he lands on a crumbling tile platform quickly do a small jump to land on the next ring or hold jump to do a far jump to a farther ring if the ring is too close. But don't get too cocky or you will jump over the ring and fall into the void.
If you want to totally cheat this achievement, use the Child and use his light weight and strange hitbox to jump of the edges of walls without changing gravity. The achievement never says you can't press left and right, does it?
The Bunny is also a viable character for this achievement, this is because of it's ability to fluctuate in his jump length.
Although he is not suggested, you could also use the Duplicator, who can jump off his duplicates to perform long jumps and has a chance of surviving when he falls off the tunnel. The width of the platform gives enough room for the duplicates to not touch the walls, so there is little risk of changing gravity.