I remember the following things about this movie:
I saw it some time between 2011 and 2015 (afraid I don’t remember when)
It’s a pretty dark movie with violence and death
The group, I believe, is partying at first, when the announcement is made.
They proceed to try to escape the (3rd world-ish) town via various routes.
Ultimately they take to escaping the town through the sewers. Here they get attacked by escaped prisoners, which wears tattoos, which has been explained earlier in the movie, is a giveaway to identify prisoners.
Ultimately, only 1 person makes it through the sewers, and arrives on the beach, where the movie ends right before a tsunami is about to eradicate everything.
This is all I remember, I hope someone can help me find this movie. It’s gotta be reasonably new (2005+ I’m pretty sure)