Note: my review covers only the single-player aspect, not co-op and multiplayer.
Star Trek is no technical marvel:
* plenty of bugs and glitches
* clumsy control system
* dumb AI
* poor graphics
However it does have some good parts:
* fun and engaging storyline
* great voicecasting and music
* good environmental designs (albeit executed with poor graphics)
* lots of variation in the gameplay (stealth, platforming, combat, etc)
You can upgrade both your phaser and your tricorder with things like: healing your partner, sound decoy, stun abilties, jamming enemy weapons, etc.
You earn XP by scanning specific items around you, completing tasks in certain ways, hacking, completing side-tasks, etc.
The game is highly linear but so are most action games. However the game does allow you to explore most of the areas you find yourself in, so your movements are not as restricted as in a Gears of War game.
The gameplay is varied where you do a mix of stealth, combat, platforming, puzzles, and other stuff such as space-shooting. However stealth and combat are the main gameplay elements.
On higher difficulties the game demands that you play tactically because you die very easily: hacking machines, disarming mines, using sound decoys, jamming enemy weapons, etc.
The playtime for me was about 15 hours, for a single playthrough.
Whenever the storyline becomes the critical pull-factor of a game, you will get mixed opinions because people like different things in their storylines.
Personally, I really liked the storyline and how the gameplay is like that of a movie; fast and smooth. So even though the game is not well made as far as the technical stuff is concerned, I still enjoyed Star Trek a lot.
Given a choice I would rather play a game that has a good storyline and characters but is bad in the technical details, than the other way around. Bodycount, Borderlands and Dark Souls are all well-made games - technically speaking - but I found them very boring since they had virtually no storylines and lackluster protagonists.
You CAN enjoy Star Trek if you think a game's storyline and characters are more important to your gaming experience than the technical and graphical stuff. So figure out what type of gamer you are before you buy this game.