If the 87% Gamestar Rating is from the German Gamestar, it is quite good.
Just to give you an idea:
They rated:
Dragon Age 92%
Splinter Cell: Conviction 90%
Mass Effect 2 88%
Mass Effect 85%
94% is the highest rating ever given and even that only twice (Warcraft 3: Frozen Throne and Crysis)
cya
Tycho