Ok let's start with saying that when a dutch movie is bad, it's REALLY BAD. Rarely something with a little bit of quality comes along(Lek, Karakter) here in holland but not often. Costa! is about 4 girls going to Spain to go on vacation, party, get drunk, get laid (u know the drill). It's also about the world of Clubbers or Proppers. Pro's who're trying to lure the crowd into their club.
I'm not sure how long it took to write the script, but i suspect somewhere between 15 minutes and 20 minutes because you're watching a bunch of random scenes for 90 minutes long. Nothing, and i mean nothing is believable in this movie. It's almost too riduculous for words what happens with the storyline. Suddenly the movie transforms into a sort of karate action thing. With a one-on-one fight with 'the bad guy in black' and cliche car chase scenes trough a watertank-car (can it be more cheesy). Also the words character-development and casting are unfamiliar to the makers.
After having seen "Traffic" 3 days before this, i fell from sheer brilliance, from a piece of art to this. This is film-making at it's saddest. And don't start about low budget. Because even with a low budget you could write a better script. It almost seems that the film-makers were too busy partying themselves to make a decent movie.
Anyway the chicks in the water at the end made it up a little bit, but for the rest of it, don't waste your money on such garbage.