Yeah I saw it , and it was actually really good. Gossling is kind of comical at times, but he actually does really well in this, and the comedy is more in service of the premise that he's a competent scientist and not-so-competent unwilling astronaut, and that he's got a weird friendship with the alien.
From a hard sci-fi point of view its really good, good enough that the few places where it does seem to veer off from known science (The solid xenon that the aliens use as a construction material) seems a little jarring.
And as a drama, yeah... it works. You'll definately find yourself rooting for the two main characters (goslings character and "Rocky" (as he dubs the alien)) and I wont spoil where it goes, but it'll get you.
Go watch it. It was easily one of the best films of the year.