There's still rules in TASing, just a different set of rules! Specifically, you have to submit a file containing a sequence of controller inputs that completes the game when played back in an accurate emulator (or a replay device connected to the controller port of an original console running the original game).

I co-authored the current fastest TAS of Super Metroid: https://youtu.be/m-Gt57ur7OA?t=2m30s We completed the game in under 2 minutes of gameplay by exploiting a race condition in the game's sprite animation system to start an exploit chain leading to full arbitrary code execution (full writeup: https://tasvideos.org/8214S ).

We used all kinds of tooling to create the run: a recording emulator with savestates, slowdown, and frame-by-frame input editing, scripting tools, debuggers, disassemblers, and memory viewers. We used memory editing tools during development to test different scenarios without having to set them up in-game first, but the actual run you submitted is completely "pure"; just an input file that beats the original, unmodified game.

And just like real-time speedruns, TASes are split into categories too. Here's the world record TAS with major glitches disallowed, by Sniq: https://youtu.be/Rr9gdQ-VkO4 Whereas our ACE TAS is more like a CTF challenge than anything else, Sniq's run is a masterpiece of gameplay that shows how far the game can be pushed beyond the current human limits. But again, it's still a true run of the game; the only difference is that you submit an input file instead of a realtime performance of the run.