This is level 51 of the Main tunnel.
Hey, this level is just a bunch of rings. Why's it so hard? Because it's a bunch of rings, it's ridiculously hard. There are 13 sides(I counted) so you need to change walls with nearly every jump. The Skater goes across a ring and a half, so he'll fall. The Lizard, well, you could use him, but I recommend the Runner. Using the Runner can let you jump between alternate rings more easily, and in this level, crumbling tiles are not a large threat, since you need to jump once you land on the ring. Also, the rings aren't connected, so feel free to make the crumbling tiles topple! But watch out for the gaps. You can use short hops aside with long jumps. Use them wisely and with care.