Obviously, including all of them would be a huge undertaking, but including all of the features from SMBDX would basically make this the quintessential version of the original Super Mario Bros. Ideally, this would consist of: Map screens in between levels during the main (Classic 1985) mode. Difficult, due to having to make new maps for The Lost Levels (9 through D at least) and Special levels. Also, map skins would (maybe) need to be accounted for. Challenge mode. I guess you'd just need to find new hiding spots for the red coins and Yoshi egg in the Lost Levels and Special levels. Versus Mode / You Vs. Boo. Would be interesting due to the possibility for lots of new maps for these modes. Local multiplayer or even online multiplayer would probably be pretty nightmarish to implement though. High Scores. Maybe in the form of an online leaderboard? Album. Essentially just achievements. Could be greatly expanded upon beyond the ones included in SMBDX. Toy Box. Mostly worthless. If there's anything from SMBDX that doesn't need to be added, it's this. I doubt any of this will happen, but I can dream!