Here's the notes used to make this guide. Note that you may find better/faster strats than what's here, so I encourage exploring and playing with the game. I feel like the last level especially can be cleaned up pretty significantly.

Basics

Donuts:

Powdered:

Simple throw forward projectile, deals 1 HP (1 sword swing). Used in: 5-6 on Pigg City boss, 12+ on Forest 1 Dragon boss.

Chocolate:

Heat seeks enemies, deals 1 HP. Enemy needs to be on screen before the donut is thrown or it won’t know to hit it. Used: 6 at the end of Forest 2 on Jesters, 6 on Phase 1 of final boss.

Crullers:

Heat seeks enemies, and deals 2 HP. Same rules as chocolates. Used: 1 at the end of Factory 1, 4 during Swine City, and 1 in Forest 2. 12 on Factory 2, 2 on Lion, 10 on boss.

Frosted:

Heat seeks, instant kills normal enemies (6 HP?), and follows you around. Disappears when there aren’t more enemies to kill. Frosted donuts can kill things that show up on screen after they are thrown, and are very powerful. Used: The 2nd half of Wolff Castle.

Damage Boosts

You use damage boots a ton in the run. Damage boosting in this game involves running through enemies/hazards once hit, and you aren’t actually rebounding off enemies to reach something you otherwise couldn’t. Spikes and Deep fry invincibility frames are far longer than normal enemy hits, so try to use those mostly.

Non-Intuitive mechanics

Running into a Jump gives extra height

Holding up in blowholes gives extra height off a jump.

Spinning off a blowhole jump makes you invulnerable, and should be used a lot.

You can throw donuts faster in the air

You can jump off a butt slam without the slow down, but it seems like a tight jump. It may be frame perfect when the box breaks.

Pigg City

Surprisingly hard to get it consistent but straight-forward. Grab first 2 crates for 12 powdered Jump faster through the last archer for ~1 sec save. Throw 5-6 donuts and/or sword last enemy.

Forest 1 (enter w/ 6-7 powdered)

Grab powdered from tree crate near start. For dragon: have 12 donuts going into the fight, stay on edge up top while spamming donuts, then grab 6 more and finish. off boss. You need to destroy both ears before being able to finish off head.

Factory 1 (enter empty)

Damage boost basically everything except rats. Grab Crullers before last hole. you need 1.5 HP+ when you fall in. Kill Jester with a swipe then cruller.

City of Swine (enter w/ 5 Crullers)

Cruller use: One on 4th Jester in level after a swipe, where you need to climb up. 2 on first Lion. 1 on the last guy. (archer) Stay in the middle of the screen for the boss, he follows you so staying on the edge can make him stay off screen a lot longer. Hit him once, and run the direction he came from to set up the next hit. Can also get a double hit but you risk him flying off if you miss the 2nd hit.

Forest 2 (enter w/ 1 Cruller)

Try to conserve life in fist half, easy to bleed HP. You can skip the underground here with a tight jump from blowhole to tree. Use the cruller on the archer in front of the lift and 3 bombs. You want to get to the right of this platform ASAP to spawn the next platform quicker Grab 6 chocolate donuts from tree ~halfway through level. Run past first Jester at end and kill back 2.

Factory 2 (enter empty)

Front half is damage boosting through what you can and staying on top layer of conveyors. 2nd half has two route choices here:

1. 6 more crullers, but longer level/more damage boosts. (on average, about ~1HP, I kill the lion w/ 2 extra crullers vs damage boosting through it to save .5 HP)
2. Skip the crullers, but harder/slower boss fight. From what I can tell, the crullers route is slightly faster and much easier.

Road to Wolff Castle (Pigg City 2) (enter empty)

Basically same route as the first level, except you go up in front of the blow hole tower, and attempt to kill a bomber with a jump over to him. You can also get the last checkpoint and die to refill your health, if you find yourself with 1-2HP at the end of the level and fear dying.

Wolff Castle (enter empty)

This level is huge and just requires knowledge of the route. If you intend to speedrun this practice it a lot, it’s easy to lose a ton of time or entire runs to this level. Dboost through a lot, and get 8 frosted donuts midway through. 2 more frosted donut pickups through the end for a total of 12. Keep moving forward, the level lags a lot and going slower/killing stuff can often cause more time loss and HP loss than just running through. Try not to fall in the climbing sections, it’s often where you can lose the most time. Take a slightly longer time to climb if it means consistency. Final boss: Grab last box in the game, 6 chocolate donuts. Phase 1: Try to stay still in the center , it prevents the boss from doing much. Hit with the sword ~7 times and the donuts. Phase 2: Hold jump, and spam sword and left and right. If you can jump off a box, the higher hits seem to be more effective as well.