It looked fanfiction, considering all the tired plot devices and recycling of previous Star Trek material. Not quite as bad as I, V or First Contact (at least it didn't have hippie drunks or religious maniacs and wasn't quite as slow as TMP), but close.
It gave me some good fodder to beat up on for the film class I'm in, though. I like to recycle, so I'll just copy and paste that in here:
Star Trek: Nemesis is an exceptionally mediocre film. It excels at nothing in particular other than blandness, and seems more like a remix of elements of earlier Star Trek films rather than anything original.
Suspension of disbelief has limits, and this film shoots past them at warp 9. It begins with a rather oddly humorous scene that sets the tone: the entire Romulan Senate turns to stone and then cracks into dust on the floor (in slow motion, naturally) due to some green light, later revealed to be a new type of radiation. Never has it been more unintentionally comical to see an entire government assassinated. This happens with no real introduction to motives and certainly without giving the audience reason to care... it simply comes off as over-dramatized and uninteresting, inserted as a halfhearted attempt to explain later events.
On the Enterprise, pieces of a deactivated android in a distant solar system set off an audible alarm on the bridge. It's quite odd how positronic signatures never did that before even at close range... never was the Enterprise able to locate Lore from a distance by any such method, and yet now a positronic signature in another solar system sets off an alarm simply because the writer (if there actually was one) couldn't be bothered to think of a reasonable way to bring the ship to that planet. The next blatant plot device is an ion storm, which conveniently lingers just close enough that they must send a shuttle down to a planet rather than use transporters, and just close enough that scanners are interfered with enough to not be able to precisely locate the positronic signature (which had been so easily noticed light years away). Simply because somebody wanted to film it, they roll an open-air jeep-like vehicle out and drive around recklessly. Somehow, in the 24th century it's supposed to make sense to leave the very comfortable and maneuverable and safe shuttle behind in order to drive around in a heavily armed jeep that might be out of the 1940s (excepting the phasors). Of course the audience knows that this is all just for the sake of making sure they're out in the open so that natives in tanks can appear and begin shooting at them... which is in turn so that the director can show them driving over a cliff (in slow motion, naturally) to just barely land their truck in the hovering shuttle. All this time, it's unclear where the film has gone or if anyone remembered that there was supposed to be one.
Later on, yet more plot devices appear. Most notable is the invention of the magic transporter pin. Conveniently there's only one of these, as though Data couldn't carry two or three, especially when he knows he's going to rescue someone. Also conveniently, it has the curious ability to function even when the transporter has just minutes earlier been very clearly established as offline. Although perhaps excusable as a device most every action movie resorts to, the Remans must inexplicably leave Picard alone with only one guard just long enough for him to escape. The way in which Picard was cloned to make Shinzon, the choice of Picard as somehow the most key person in the Federation to want to clone, and the way in which a clone of a human would become the leader of the Remans, is all left unexplained for the simple reason that there is no reasonable explanation. The worst spot, however, may be the scene where Troi locates a cloaked ship via telepathy -- this is highly overdramatized, with errie music and rectangular lighting focused on her eyes completing the unintentionally comic moment which looks as though it came from an old episode of "In Search Of...".
The acting has one minor bright spot, that being Tom Hardy as Praetor Shinzon. The villainous part is portrayed very well, with a sense of complexity behind the lines. For the rest of the cast, early on the dialog seems forced and unnatural (though perhaps the writer is more to blame than the actors). Later there isn't as much dialog, as it gives way to explosions and shooting, which is by then a welcome relief from having to listen to them read such pathetic lines. As Picard, Patrick Stewart seems to be either flat and disinterested, or oddly cheerful at the wrong times. No longer the reserved, diplomatic commander, he seems playful and reckless. As he prepares to ram his ship and perhaps see many in his crew die, he smiles while talking to Shinzon, as though he gains so much fun from preparing to do something his clone doesn't expect that he can be genuinely cheerful as his crew faces possible death. The sense here is that the characters don't take the danger seriously, Picard and Data especially acting as though they might turn around and say "oh, don't worry, it's just a movie", and so it becomes impossible for the audience to take their danger seriously either. When Data is killed off at the end, it's oddly incapable of bringing forth any real emotion... there's no real lead up to it or indication of a fatal choice being pondered, so it has no particular impact.
Overall, "Star Trek: Nemesis" seems to be a weakly contrived excuse to blow things up. Special effects are where most of the budget seems to have gone, but while they show detail and financial commitment the effects are often strangely out of place and distracting. The effect at the beginning of the film of Romulans breaking into dust on the floor of the senate is clearly intended to evoke horror, but accomplishes only mild amusement. The choice of a neon green glow with swirls in it to be the deadly radiation which threatens the universe is also odd, as it looks more like an interesting kind of light than like anything threatening. The film throws together elements from previous films, notably making Data replay Spock's exact role from Star Trek II and making Shinzon's whole situation a direct copy of Khan, and nothing in the script (written by long-time fan John Logan) seems particularly original or creative. This is nothing more than a rehash of familiar ground, presented less effectively than ever.