I found it to be very entertaining, even if it is improvable. Although if you're going to bother improving this run, I'd suggest making it "co-op" for some of the extra shortcuts and optimizations that are only possible with two or more players. You could have a player throw another player while traveling on a moving ice block and perhaps that'd really get some insane speed. Or maybe a player with a block of ice and on top of that ice is another player holding a block with a player on top. Player 1 throws their block, Player 2 then throws their block a second later, and that would give a stacked speed (So say if the regular block moves at 5, then that block throw from the moving block would move at 10). You could get the most out of each level having four players, each with a designated power up (one Mini, one Penguin/Ice, one Propellar, and less useful fire). The beauty of a co-op run is the bubble system. More often that not, you won't have to worry about input for the other three players.

Actually, there's a obstacle in making co-op TAS. Even though one player can boost by assistance from others, the game does not end unless all player reach the flag. So merely just sending one doesn't have any merits. But there are some solution to this problem, too. If the stage consists of several levels, connected with pipes, then you can send one player to enter the pipe, because the game force players to warp it. Also, you can control some players to take death on purpose so that you don't have to wait for them(but losing all power-ups they had). Anyway, it seems that controlling more then one player on this game is terribly hard.