Huh... guess it's time to make my first post here.
I can also vouch for Scurge: Hive as being awesome fun. Very fast paced, and the Scurge infection percent count really keeps me on my toes. And the awesome thing about this game is that you can definitely leave off at a certain point, forget about the game, and come back to it a couple weeks later and not take too long to remember what you have to do next. I'm the kind of gamer that eschews the must-complete-ASAP mentality in favor of playing games when they'll feel most enjoyable -- so I play certain games for just maybe 15 to 30 minutes at a time. As such, I'm still not done with the game (and I bought it shortly after it was released!). But, the structure of Scurge: Hive allows me to play it that way -- and it's fun every time I do.
As far as which version to get -- I'm really not certain what the IGN reviewer was talking about. I have yet to see the GBA version in motion (unless the trailer was the GBA version?) -- but comparing IGN's GBA screenshots to what I see on my DS, they look virtually identical. As such, I'd say go for the DS version -- not only do you get more screen real-estate (which helps), but the on-screen map actually does help out a bit (and can be manipulated via the touch screen while the game pauses itself for Save messages or cinema scenes). That, and if you're going to be playing it on a DS anyway, you can use any of the six buttons of the DS for the game's four commands, instead of being restricted to the GBA's standard four. (For me, that helps out, since I've got Y to shoot, X to grapple, A to switch weapons, and R to jump.)
Now, Contact -- there's a game where your mileage may vary. I enjoyed the game's good music, the somewhat slower pace of action (a good balance for the faster-pace games I've got), the often quirky humor (and references to both classic and very-recent geek pop culture), the varied and often-nice-looking environments, and the way the game centers itself around the breaking of the fourth wall.
I can say that I didn't enjoy the grind the game sometimes required -- especially a money grind to acquire at least one item in the game that was required to progress. (... I've been burnt out on grinds from MMOGs.) And others, I know, said the ending left them feeling a bit empty.
The game, in general, though, left me with a good feeling.
Rocket Slime -- I haven't gotten too far on this one either -- but I can at least say this game has one of the happiest tones of the games I've played so far. And I'm having a good time playing it.