Level 1 only needs this hard af thing that I like to call "no bonk jump" or nbj for short. This is where you jump just right so you dont bonk yourself on any platform. Such as the first jump you'll do in the game. Right as you get to the brick floor theres a stack of 2 1 1 2 just on the edge of the last 1 and start of 2, you jump and if you did it right youd have made it across cleanly and without bonking. (Although normally you wont be using nbj because of its minimal time saves and difficulty only go hard with it in areas your confident in doing so.

Level 2 theres a platform of 2 bricks side by side, jump on the end of it than succeed it with another jump to avoid bonking yourself. You will of course be led to the sliding ramp which you'll see again throughout the game, all you have to do with that is jump on it and jump off at the exact moment you can (although this is normal logic in hindsight I didnt do this and lost a couple milliseconds.)

Level 3 you finally get the action button, here you just gotta double tap it while holding right until you reach the cat food, unless your going 100% do not double tap until you reach the wood platform at the end where than you double tap.

For level 4 there is only 2 things to note: 1 you can teleport while inside the cross 2 do not push the movable object you can jump across just finely where it is (Note: you already know this but it tells you by having a sign pop up over the cross' and other things you can interact with the action button.)

Level 5, again you can teleport from the 3rd wooden panel. No need to over extend. Dont feel the need to push the box too much just get it to the end of the button and you'll be fine.

Level 6, no need to use to first 2 crosses just get past them without being too trigger happy, although the 3-4th one get to immediately.

Level 7 has the first check point, only remember to catch the ride as fast as possible or lose precious seconds. Theres also a clip where on the down turn of the lift you can spam

Level 8, I'm gonna give you the same advice I wanna give my older self. DO NOT just jump right into the saws, miss first cycle, or go the intended way after you put the box on the buttons just go the way you came from.

Level 9, you meet the moving cross box & cannon. Use the box and dont get shot. A good exploit is to restart as you hit the checkpoint to remove the bullets already there allowing for easy crossing. If you did it right you should meet the red dude without having to stop and bait him.

Level 10, dont try to bait the red dude, just spam that action button till you reach the top. Dont be shy around the moving platforms because if you do it right you'll meet them at a cross roads going by them easily.

Level 11, all you gotta do is wait a bit until the elevator than make sure you pre push the box over the locked big box and you'll be optimized.

Level 12, dont be a wuss, get in there and one cycle it. No need to reset the cannon or platform (you COULD reset it and you WOULD be able to get on the platform faster but that's eaten up plus some for the mandatory AD youd have to watch and unless ad time is subtracted from the total than I dont know what to tell you.)

level 13, for this one you can go wherever you wanna go to first, it doesnt matter. To the left is just a box pushing sim. On the right side you have to not push the block over the button but otherwise stand on the button yourself and press the switch. This is to not have the platform constantly moving aka easier runs.

Level 14, no major routing nor speed tech, just go fast and maybe try to jump over the second red dude.

Level 15 is a speed contest so I'll walk you through the various areas and the few speed tech I know for it. The first is the nbj you do from the box, it's pretty self explanatory just go and be done with it since it's really easy. The second is the cramped space next to the wooden platforms which you can either fall from and be dumb like every other runner or on the very tippy edge of the platform jump and make it just to the edge of the platform to make one of the most uselessly hard jumps in the game. On the saws which you'll run into you can jump ever so perfectly that you can run past smoothly without dying. (I know, I know. No need to thank me.) Otherwise theres nothing more to say.