where you get to level 150 in all 5 stats for all 4 ducks

I had a similar idea for this a while back, but it involved all of the in-game achievements which include flying backwards, as seen here:

That would only require one duck to have all of their stats maxed though. A combination of our ideas could be an interesting category, but idk if it's different enough from All Duck Types to justify a main leaderboard category.