This is the twenty-first level of the Main Tunnel.
This is the first level which is green. Use the Runner to maneuver along the green, or use small jumps to get on the crumbling tiles. If you are confident enough, use the Skater to jump over big holes.
Use the left and right keys more, and rely less on jumping. If there are multiple holes in front of you, and you are not fast enough and quite frankly won't clear the gap, do the high jump.
If the jump needed is too far away, try to change gravity in the air and land on a wall or nearby tile. If your jump is not far enough, try to land on the crumbling tiles in the hole, and use the short jump to return to the normal tiles.
In this way, you can pass this level with a lot less attempts than if you just tried and hoped for the best.