Quite frankly, Brink looks pretty cool. Whether or not I purchase it hinges on the answer to my following question: How many of the Achievements are based about single-player? Can I get a perfect on this, or do I need to go multi for it?

Now, don't think I'm some shallow Achievement hunter that only buys games for Gamerscore; this is not the case. The reason I care is that I'm sort of trying to save some cash, so I'd like to know if it is a worthwhile purchase or not; otherwise, I'll go for another game that I like equally as much, but with more achieveable Achievements.

the single player and multi-player are the same so most likely they unlock on either one ^_^

The single-player, and multi-player are the same. So it doesn't matter which one you play really, you can get them all by doing either.

Well, it certainly looks like I'll be getting Brink then, huh?

yes do it

Lets hope. Have you see the achievement list yet?