Wait, this Wario Land 4 description seems off to me...

[CM30]

From Nintendo UK's page:

Loot-loony Wario has discovered his biggest score yet: a fabulous golden pyramid filled with riches. Trouble is, its denizens don't want to give up the treasure easily – but that hasn't stopped Wario before!

In Wario Land 4, the greedy hero finds himself no longer invincible, as in his previous platform adventures. However he can undergo amazing transformations that aid him in his quest; now he can become Bat Wario, Bouncy Wario and even Zombie Wario!

Four guardians stand jealously over the four sections of the pyramid. Wario will either have to defeat each guardian, or activate a switch and escape before time runs out!

Err, did anyone else read that as 'defeat the bosses or escape them', rather than 'defeat the bosses in some levels and escape via portal in others'? Seems almost like it's saying you can run away from boss battles, which is wrong.

On another note, I will say I like their trailer for the game; about half of it seems to be showing parts of Crescent Moon Village. And since that was always my favourite level... yeah, good choice there.

 

[Boris Carloft's Car Loft]

Then perhaps it was written earlier in development and nobody caught it.

 

[607]

Well, I think they mean the right thing. They just wrote it kind of unclear. I think they mean "Sometimes Wario has to defeat one of more guardians, and sometimes he needs to activate a switch and escape before time runs out!"
And not defeat the guardians or choose to activate a switch and escape.

 

[Boris Carloft's Car Loft]

Good point, there.