Hoo boy. I'm a huge GI Joe fan, and while Stephen Sommers tried to throw folks like me a few bones, this was not a good flick. I had a lot of problems with some of the core decisions, like making the GI Joe team an international strike force when the original tagline of "A Real American Hero" made that an odd choice. That said, the casting seemed ok, and outside of some odd choices like making Ripcord a pilot, I was still kind of psyched going in. After all, outside of big nerds, who really cares that Ace, not Ripcord, is the main Joe pilot?
So I went out and checked out the film, knowing I had some underlying problems that I hoped I could get past. There were more problems than what I expected. Snake Eyes' mask had a mouth! Ripcord hooks up with Scarlett, with barely any relationship with Snake hinted at for our tough redhead! Baroness is a BRAINWASHED hottie who had been engaged to Duke! Not only that, her nerdy brother is Cobra Commander. These are all odd plot choices that overly complicate things for normal viewers, and stuck in my craw as a Joe fan. These were problems above and beyond "Accelerator Suits."
Add in the frenetic pacing, the cartoony CGI effects, and the wooden acting from most of the cast, and I'm afraid this is skippable. Sommers tried, especially with some decent bits for fans like Breaker liking bubble gum (comics) and Heavy Duty yelling "Yo Joe" (cartoon). I particularly liked the ability of the core cast to survive explosions and gunfire that destroyed supporting characters (Duke in particular rides out a point blank explosion that should have atomized him). It is probably still worth watching, but I would advise against seeing it in the theater.