Breather Level: Round 5. It's fairly easy, there's only one real boss, and the level itself is a lot more pleasant looking and sounding than any of the others. It comes right before Round 6, generally considered to be the hardest.
The numerous bloody hellscapes which compose the levels are this for some, as are the final bosses, Chameleon Man, and the game over, level start screens, and ending.
The Jinmenken, those human-faced dogs that serve as one of the game's many weird enemies.
The ending. Bert gives Mark a present. He opens it. A beautiful princess pops out! But the princess then turns into a monster. And then more monsters appear and chase Mark. And then his flesh starts melting off his bones. Luckily he wakes up! It was just a dream! ...Until he leaves for school and finds Bert waiting at the door.
Most of the differences in the beta version involve more on-the-nose (and therefore Lawyer-Unfriendly) parodies than in the final game, but the pre-release title screen has a giant mouth filled with blood instead of green slime, and several of the bosses that parade by look much freakier than the ones you actually end up fighting, with blood dripping from their eyes and mouths and an overall grislier appearance.
Scrappy Mechanic: There are 3 bosses in Round 7, and you'll get the key to leave by killing 2 of them. Kill the 3rd one, and he takes the key with him, forcing you to restart from the very beginning.
That One Boss: The Giant Dragon in Level 8. Not only is it constantly swooping in and colliding with you to ravage your hit points in a matter of seconds, but its weak point is extremely hard to hit for exactly the same reason.
That One Level: Level 6. An extremely confusing Haunted House maze, filled with fast-moving blue ghosts that swoop down from overhead and a continuous howling wind sound effect that starts out pretty neat but, when paired with the background music, quickly becomes annoying.
What Do You Mean, It's Not for Kids?: The game was released back when there were no ratings for games, and it has gory visuals throughout. And this is after it was seriously toned down.
Milo is tenth in the credits, but is highly popular due to his actor (Lance Reddick) and how he combines being a "preening cult leader" and Only Sane Man as he tries to use both words and force to keep the other members of his Serial Killer 12-Step Program from killing the protagonists.
Iris fades out of her initial deuteragonist role as Alexis becomes more prominent and her #2 spot in the credits is seen as a downplayed example of Billing Displacement, but she is still considered a major highlight of the film. This is due to how she is a Pregnant Badass who is the most reluctant of the thieves and is the most expressive character when it comes to reacting to the violent craziness.
Narm: Casper being an Instant Expert with a katana in the final act is viewed as being ridiculous rather than awesome by some fans.
They Wasted a Perfectly Good Character: Becca's fear and discomfort about being at the party (even though the homicidal guests aren't killing people anymore) and the way she accompanies Milo the group leader attract a lot of interest. She commits suicide as soon as the main conflict gets underway and her background and motivations are never explained.