[TAS] Mari0 in 01:11.92 by Masterjun
Mari0 is basically Super Mario Bros. with portals.
The route is pretty simple: Enter the 1-2 pipes before they have fully loaded. This brings you to the minus world -1. Quit and continue the game from there, bringing you to 8-4 to finish the game.
Portals can only be placed if there are two solid tiles next to each other. Once you shoot a portal, there is a 12 or 13 frame delay until you can shoot the next one.
Your running speed is capped at 9 tiles per second (the game runs at 60 FPS). The vertical falling speed is capped at 100 tiles per second. Using portals you can exchange X and Y speeds giving you up to 100 tiles per second horizontal speed (for reference, Mario has a speed of around 88 in 1-1).
1-2 shows a clip I found when moving left when falling into a floor portal. By positioning yourself correctly, you can clip into the ground if there is a block underneath the left block where the portal is on (which is why I couldn't clip directly through the ceiling).
It's quite possible there are other routes in the level which turn out to be faster. Platforming with portals is quite the interesting task with unintuitive tricks you can use.
It's why I had a lot of fun TASing this so far!
Movie file (.ltm): https://www.dropbox.com/s/mdqjnmiu901...
[Mari0 in libTAS]