This level is called "the surprise," created by user GOONIN_UP_IN_HEA.
It is gloriously, unintentionally surreal. You might be thinking, "Surreal!? lol" but calm down. To have fun with this, you only have to take everything in the level as literal - just as the level presents it to you.
Think about what was running through the kid's mind when he made it. Just watch.
Run past the glass wall background. As you'll note, there's really nothing here besides the weird object running back into the distance.
Come across the strange skull creature, sitting in the middle of nowhere.
Read what it says.
i need your help this man kicked me out the level a long time ago lets make a one and then lbp2 will be worse than lbp
Realise that the creator has inadvertently put you in some weird space or dimension known as (quote) "out the level." Realise you don't have a clue what "the level" actually means, since of course you are paradoxically in a level right now.
Ask yourself: when it says, "the level," could it be that the weird skull thing is actually referring to
this level (i.e "The Surprise"), somehow? Is the skull thing existing within "The Surprise," yet somehow also "kicked out" of it? Look at him. Look at the actual universe present in this level (a level that is stripped of any attempt to ground it any kind of solid, earthly world) and come to the conclusion that this actually kind of makes sense, on some weird David Lynch-esque dream logic.
Run further and see this peculiarly placed teddy bear. What's creepy about it is that it sits perfectly still - that is, until you approach it. Then it starts to move its arms and head, slowly.
Then the teddy bear cries;
dont trust that man he is bad a a a KILLER!
Notice how the so-called teddy bear just spoke to you with the voice of a barking dog.
Who do you trust?
Keep moving until you see the end of the glass wall. There's this evil-looking cowboy thing sitting there - perfectly still...
... that is, until you're close enough to touch it, and then it starts laughing, its mouth bouncing on hinges, up and down.
The cowboy itself says nothing. It makes no verbal sound. All you can hear are the bolts and pistons operating its jaw, grinding like some sort of wind-up toy.
Keep progressing, and you'll see this.
Yes, that is a king crocodile, snapping it's jaws rhythmically back and forth into thin air, not quickly but sharply - powerful. And behind him; what is unmistakably "Leela," from the FOX TV show
Futurama, posing rather sexily, her head subtly swaying back and forth in a kind of pleasant, supple rapture.
Leela says:
you want some fun at my house then KILL HIM
Press on and see who Leela want you to kill - your introduction to this crazy world - the poor skull-creature.
And he's already dead.
Shoot him with the paintinator and the pain bar empties with 1 hit - this does absolutely nothing.
Go further and see Leela, still doing that sexy pose and not saying a word.
A tense, sinister kind of song starts to play. (The beginning of "The Battle of Ice.")
And that's it, apparently.
This level does not end.