It seems you've stumbled upon a leveling system that's gone haywire. Levels 1-9 have been replaced with levels 10, 15, 20, and 22. Don't ask us why.
You're now level 22, which means you have access to even more levels that are completely untested and possibly unplayable. Congratulations!
Explore Level 20 Anomalies View Secret Level 22 Content (if you dare)