That's... Wha? How can you speedrun a game without having played it before? That's just going to make you a lot more likely to run into places where you learn something new is possible that forces you to redo everything you've done. I wouldn't start a tool-assisted speedrun unless I already had a pretty good idea of how the whole thing was going to look. Faulty assumptions usually come in from NOT having played the game enough.
If I'm trying out an emulated game for the first time, I like to start with a few "genuine" plays where I just see how far I get without using savestates. After those few Game Overs, I'll have an idea of the game's difficulty and pacing. Then I'll do a "serious" play where I complete the whole game with as much savestate abuse as necessary--possibly more than necessary if I'm feeling perfectionist about not missing anything or not failing anywhere. I might even use frame advance to see what improbable maneuvers can be made or just to watch some speedier animations frame-by-frame.
Then if I really like the game, I may learn how to play the game from start to finish without savestate abuse, see if I can pull off any strange combos or sequence breaks along the way (where I might allow savestates again to check the possibility), or just start checking how feasible it would be to make a full TAS--but those prior activities are usually important to planning the TAS properly, I feel! So I guess I'm not like other people who can look at a new game, whip up a decent strategy for completing a good TAS, and quickly finish and forget it. I basically have to be completely in love with the game over a period of months for there to be a chance of finishing a TAS, and the game can't be so complex that I can't be 100% sure I've got the perfect route and mastered the physics, or the perfectionist in me will just worry too much and never get anything serious accomplished!
put yourself in my rocketpack if that poochie is one outrageous dude