This game doesn't seem to work on disney xd or on the disney channel website. How do you play it?

We have a whole guide on how to play it :) https://www.speedrun.com/paftod/guide/a1vhk

If you don’t understand how to do any of this, you can just download an app called Flashpoint Infinity and play it from there, although it lacks fullscreen support.

(Also the game download link on this guide seems to be broken, here’s the updated one: https://www.speedrun.com/patches/Phineas_and_Ferb_in_the_Transport-inators_of_Doooom_tn0cb.7z )