I have noticed that some leaderboards are missing. Those are:

-2P Happy End -1P w/ Extra Floors

You can probably skip the latter, but there would still be a leaderboard missing.

I 2nd this notion. We have ours listed under 2p Bad End, but it's really "2p True/Best End" which is played in supermode and the secret levels are included. With the enemy differences and a dozen or so extra levels it's not a good time comparison to lump in with the Bad End category.

There could be an additional "2p Happy End" category that is regular mode and secret levels (note that the ending indicates it's not the "true" ending). I have done these runs as well.

@ letcreate123: "1P w/ Extra Floors" would still be a Bad End btw. What I've done is played 2p by myself and just rejoin the 2nd player just before defeating Super Drunk. Then it becomes a Happy End. I agree that option could be skipped.