Watched Cabin in the Woods, it's a hilarious good time. Two comments:

it's basically one horror flick to rule them all. Second, it plays on the myth that man is in control, and despite everything, it's nothing but.

And yes, there are mermen.

No, not that type, this type:

Richard Jenkins and Bradley Whitford are hilarious. Even Sigorney Weaver makes a surprise appearance in the end.

On another note, Cube-0, Cube, and Hypercube are all really good movies too and this movie reminded me a little bit about it (though it reminded me about 13 ghosts, hellraiser, texas chainsaw, 28 days, and dozens of others too).

One of my favorite parts is when Jenkins in explaining to another employee how Zombies and Redneck Zombie Family are entirely different species, just like an Elephant and an Elephant Seal are entirely different.

http://scifi.stackexchange.com/questions/14923/which-of-the-items-and-monsters-were-references