For a trailer it seems pretty long although I think it's not a bad thing here as it shows some of the game's concepts. I also like that there's actual gameplay shown without having a cut every one or two seconds. Many other trailers show a million short slices of gameplay from which you can't really tell what it's like to play the game.
Overall, I like it. It gives a good impression of what the game is about and it's done pretty well.
Edit: some nit-picking:
- It feels like the text at the beginning is shown a bit long ( not sure how fast other people read, though
)
- the outro seems a bit long, too. especially because the music cuts out much earlier