Maybe 3-4 runs could be made for the game
A first one, like PikachuMan said, where you unlock and beat Lost Levels to get to the credits (I really like the idea, and the credits song too).
A second one, where you make maximum score out of every Challenge Level.
To get the best score, Koopas shells are the best, since they can provide way more points than the timer (with stair glitch, last frame kicking, or just bouncing against a wall), so it would maybe get a bit boring since maybe half of the levels (16 out of 32) would be : get to a Koopa, kick it until timer goes down, run to flag.
Thus, most of the time (let's say 260 seconds out of 300 on the timer) would be spent kicking a Koopa Shell.
But since the time is still short, and 32 levels is not overnumbered, it would still be interesting to watch as maximizing the score is too damn challenging on this game.
I was completely amazed and seduces when I saw the records of this guy :
https://www.youtube.com/user/87ThePassenger/videos (he has the records on nearly every level, but the videos aren't really known)
Maybe a third one where you only focus on Medals (Eggs, Red Coins, Score, Score Bar).
Since some achievements can't be earned in TAS because they need a link connexion, I don't know what to think about an all achievement run.
And a fourth for You Vs Boo completion (a TAS of it already exists).
Also, for Koopas, I'm not sure about what strategy gives more points in a set amount of time between the last frame kick and the repeated bouncing on a wall.
