Alice: Madness Returns

Story-Related: Can't be missed. Unlocks at the end of ACT 5 when the true enemy is revealed.

Tips for the level (spoiler alert):

-The Rolling Dollhead sections are called "Off With Her Head" sections--and completing the second of these grants you an achievement if you can manage it under 6 minutes...fairly easy.
-There are some interesting switch puzzles in this level and many times it may seem like failing them puts you in a locked room--there is always a way out if you manage to only halfway complete a puzzle (say you need to pass through three doors and you only manage 2 in time--there is a way back to the start of the puzzle).
-Kill the "Bitch-babies" by either deflecting (LT+A) their green goo attack for a one-hit kill, or teapot cannon for the same.
-There are an absurd amount of teeth in this level--especially towards the end--so use this as an opportunity to upgrade your weapons. I personally had them all upgraded by the first checkpoint of the level, but you should have at least the fully powered vorpal blade, pepper-grinder, and teapot cannon after leaving the level--otherwise the final battle may be difficult for you.
-The mega-dolls are invincible while guarding with their arm(s) so either unload with the teapot cannon and hope you can kill them before they start whoring block or get them to use their slash attack which leaves them vulnerable for a while.
-Kill the Drifting Ruin immediately--because they are the most annoying enemy in the game.
-You will have to fight a Menacing ruin at the same time as an infinite amount of slithering ruin midway through the level--and honestly this was the hardest battle for me because the damn ranged weapons kept locking onto the worms. Try to lure them into one spot with a bunny-bomb, then focus on the big guy until he dies.