Altered wasn't a bad movie. I am a huge wimp when it comes to scary and violent films, so I can't say I really enjoyed it, but for a low-budget film it was still high quality.
It stands out from other awful horror flicks because of a few different things: 1) It's got backstory that is slowly revealed through the movie, thanks to decent writing, 2) it's got believable characters and relatively good acting, and 3) most of the gore and the aliens look incredibly and terrifyingly real. Again, I'm not an expert on the genre, so I don't have a lot of experience with alien gore, but it looked very convincing to me. At least, I saw through my fingers. Let's say it is definitely worth that "Entrails" tag someone gave it.
(Guys, if you want a movie to watch with your easily-scared girlfriends so they will curl up in your arms, this is definitely a good one!)
So if you usually like movies in this genre, I think you should give Altered a try. It isn't a masterpiece but it's worth the short 87 minutes to watch.
8/10