It's an incomplete game. Storywise and gameplay wise.
The beginning starts as a Halo ripoff of some sort. The game gets better as you get new "powers" but some of them are extremelly dificult to control in a battle situation. Also by the time you get the later powers, your character will be too overpowered. It's always nice to kick alien ass across the level (literally) but something challenging would be much better. So the game starts being a boring "play only for the storyline" bit which wouldn't be so bad if the plot made sense which it doesn't, this applies specially in the last levels, and if it actually ended. When you finish the last level, you are awarded a cutscene with a cliffhanger so large it makes FreeSpace 2's ending sound finished.
I don't advise this game to anyone (perhaps if they find the game for 5$ or something) unless they really like to kick alien ass across the level. It's a fun experience but as I said, not challenging and not worth paying when you can have better stuff to spend with.