I suppose there are some people who would take the extreme difficulty in describing the plot of John Dies at the End as a plus, but they shouldn't because despite some occasional gross-out laughs in an Evil Dead 2 sense, the movie is a scattered, inconsequential mess.
Opening with a weird series of scenes involving killing a guy, hacking his head off with a hatchet, breaking the handle, replacing the handle, chipping the head, going to the store to replace that, then the dead guy showing up with his head sewn back on with monofilament, JDatE opens with buzzy WTF energy as we're introduced to the very Caucasian David Wong played by the familiar-looking-but-new Chase Williamson. He's talking to newspaper reporter Paul Giamatti about some drug called "soy sauce" that he's on which gives him visions of different points in time and how his pal John and he deal with aliens from other dimensions and spider monsters and the ability to read other people's dreams and some other crazy stuff.
The problem with providing a plot synopsis is that the time frame and levels of reality jump all over the place meaning nothing is ever what it seems and after you realize that none of this matters; it's all just a pastiche or random collage of occasionally nifty moments like the monster made of meats stored in a freezer or how John (who died in the middle but is alive at the end thus the title is a lie) communicates with David via a bratwurst. But it never amounts to anything. I've heard rumbles that you need to read the source graphic novel, but that just means the movie has failed all the more because you shouldn't have to read the source material to appreciate a movie. (See The Lord of the Rings for a prime example.)
Directed by Don Coscarelli, the man behind the Phantasm series and the equally wildly-overrated Bubba Ho-Tep, JDatE gets a nerd pass from the easily-entertained nerds for just being odd, but while there are some interesting concepts rattling around, they don't add up. Bubba Ho-Tep had a similar problem in that the basic premise - Elvis (played by Bruce Campbell) is alive (it was an impersonator who died), but living in a nursing home with JFK (played by Ossie Davis!) and they have to battle an Egyptian spirit - was cool, but it didn't go anywhere. It felt like they stopped once they said, "Bruce Campbell is Elvis and JFK's an old black man."
John Dies at the End falls into my "not terrible, but not any good" zone where stuff like The Crazies lives. It's not so bad that I need to warn you away from wasting your time, but there's not much to recommend you spend the time on watching it. The less impressed you are by random weirdness, the lower your need to seek this one.
Score: 5/10. Catch it on cable while multitasking.