Are you a purist when it comes to adaptations, such as game adaptations of novels?

The problem is, u watch movies first (HP was good both).

I am, kinda. Usually I don't like to watch a movie/play a game after I have already read the book. For example, I think that The Hitchhiker's Guide to the Galaxy is a horrible movie. Also, I'm yet to play Metro 2033 and I fear that I might get disppointed(despite everybody saying that is it a great game), because I've already read both Metro 2033 and Metro 2034.
Vice versa is usually OK so If I can, I prefer to watch/play before reading the book.
And, of course, there are some loosely based adaptations like Night Watch and Day Watch movies who has little in common with their respective books. I don't really mind these adaptations because I consider them as two independent instances of a common storyline.

Yes I am. Most of the time I'm not satified with a novel adaptation to the cinema.

I generally like a movie to follow the storyline of a book fairly closely like the lord of the rings movies (mostly anyways). I absolutely hate it when a movie just wings it and pulls stuff out of its ass (Eragon..........)

Scott Pilgrim is the only one I can recall.
Weren't into the other book into movies adaptations.

Depends on the quality of the adaption, but generally speaking as long as the core ideas behind the story hold up I don't care how different source and adaption are. (Cases in point: Akira the manga vs. Akira the anime, Bladerunner the movie vs. Do Androids Dream of Electric Sheep the book, the various versions of the Hitchhiker's Guide to the Galaxy which all spawned from the original radio play).
There's always changes required to fit a new medium anyway.

case-by-case; sometimes it works, sometimes it doesn't.
if it works on its own, while failing the spirit of the original, then yeah, it bothers me if I was already a fan of the original.
for me, spirit is more important than accuracy in adaptations. different mediums have different capabilities and constraints, and I appreciate the creators in those mediums utilizing their strengths and avoiding their weaknesses.

No, I accept change as long as its still good or decent even.

Also I like when they change endings or story bits, really its better then seeing the same thing over usually...but many people hate when it does that.