Encourages people to play more. Rings perhaps? (Since you have rings under your body in game.) They are colored like your player. The difficulty of the level determines how much rings you get. Only verified levels give you rings; unverified levels dont give you anything.
Easy - 1 ring
Medium - 5 rings
Hard - 10 rings
Very Hard - 25 rings
Impossible - 50 rings
Rings would show how good you are at the game. Leaderboards could be set up with the top ranking players. This massively encourages playing and would heighten the community by a long shot. Level completions would feel more rewarding (obviously) and would mean more to the community. For example, beating an impossible verified level not only gives you 50 rings, but places you higher on the leaderboard, which gives you more incentive to go out and beat more impossible levels.
In the future, maybe more difficulties could be added, with varying amounts of ring rewards.
Insane (replaces old Impossible) - 50 rings
Extreme - 100 rings
Impossible - 250 rings (Top levels only, maybe top 10 or top 15 only, using .index's list)
With this, one completion won't dictate your entire skill level. Rather, the amount of rings you have would dictate it instead. The top 1 player on the rings leaderboard would be considered the best player of them all.
The potential for achievements here is insane as well. You could add achievements for reaching 500 rings, 1000 rings, 2000 rings, 3000 rings, and so on. Players would feel more inclined to progress through the game's harder levels and play more to practice.
Even if this was considered, it would make me really happy. This feature is basically a free activity boost and community boost in every way possible.
Thanks for taking the time to read this. If you like this idea, spread it around and make sure it gets to Slin or one of the other devs!!