For early runs I would recommend playing with a memory card, I think this loses about a minute but if you game over or have to quit out for any reason you'll be booted back to the title screen with no way to continue. If you play without a memory card there'll be an extra dialogue box you'll need to skip after every level.

Level 1:

For movement as Ruff you'll want to double jump everywhere you can For combat as Ruff you'll want to use the Square, Square, Circle combo. Using a gun for parts with multiple enemies is effective early on, but later enemies are harder to kill with guns.

When teleporting the first Piglot, let it follow you to the teleporter. This skips a cutscene that would play if you picked it up.

You can skip the health cutscene by jumping around the trigger:

You can skip getting the invisible Piglot:

Level 2:

In this level you unlock the power to play as Werewolf, which you'll want to do for most of the rest of the game. Most skips past this point are only possible with Werewolf, plus Werewolf is faster and stronger than Ruff.

For movement as Werewolf you want to pretty much just double jump everywhere. For combat as Werewolf you'll want to use the Square, Square, X combo (I'm pretty sure it does the same amount of damage as the Square, Square, Circle combo, but the animation is faster).

This level also has a few skips:

(Note: the ledge grab at the beginning skips a cutscene)

Level 4:

This level has 6 boss fights.

You'll want to play as Ruff for the Guardians. You'll need to make sure you have full ammo in between each fight, if you run out of ammo during a fight you can either get more ammo from the ammo crates, or use the moon genetic power as Werewolf (Don't use all of your genetic power or you won't be able to use Werewolf until you get more).

For the Armageddon fight just use the Square, Square, X combo as Werewolf (This goes for all Armageddon fights in the game).

The 2nd boss can be skipped two different ways:

Fastest method: You have to start moving immediately after respawning or the fight will be triggered again.

Slightly slower but safer method:

The boss right after the Armageddon fight can also be skipped:

There are also some other skips after the 5th fight:

I personally wouldn't recommend buying the shotgun here, it's very hard to hit the Guardians with it and it'll make the chances of getting Transfixer ammo lower. If you want the shotgun wait till level 5 or later to buy it.

Level 5:

Level 6:

For this boss you want to make sure he's in between attacks before picking up the Fake Piglot. Make sure he's not in the middle when you release the Fake Piglot

Level 7:

Level 8:

Level 9:

Hold forward while double jumping here to clip

Level 11:

You can skip the Armageddon fight in this level:

The correct orders for the music boxes are: 1: Red, Blue 2: Yellow, Green, White 3: Red, Blue, Yellow, Green, White (You won't do this if you do the Fat Piglot skip listed below)

The Fat Piglot section of this level has you waiting around a lot, luckily this entire section can be skipped:

Level 12:

Let go of the Smart Piglot once the light changes to the color you need (I dont think the bosses attacks will make you drop the Piglot while you're in midair)

Level 14:

Armor can actually protect you from the mud and it makes the level a LOT easier.

Level 17: I wouldn't recommend using any weapons as Ruff here, enemies take too long to kill and they can drain your health easily if you try this. Just ground pound as Werewolf when there are multiple enemies.

This level sometimes won't let you progress either because a door won't open or some enemies won't spawn.

If a door doesn't open you might've accidentally skipped over a trigger (this is the only reason I can think of for this happening, I could be completely wrong on this), try going backwards and activate previous checkpoints if this doesn't fix it then you'll have to restart the level.

I would recommend not skipping cutscenes of enemies spawning, this is the only reason I can think that enemies wouldn't spawn. If the enemies don't spawn you'll have to restart the level (This doesn't seem to be a problem in any other level).

Final Boss:

I would recommend playing as Ruff for this boss since Ruff's animation for picking up Piglot's is faster than Werewolf's and he seems to recover from ground pounding faster than Werewolf.

There are two spots to put the Piglot, make sure you use the same one all 3 times.