Not great, at all. I mean, I wasn't expecting much, but the plot is formulaic (when it's comprehensible), the characters and script are completely forgettable and the action is actually quite dull. Given that the film isn't even that old, the CGI hasn't stood up well either.
I was never someone who played with or watched G.I. Joe as a kid, so I can't speak of any nostalgia, but the character interactions are just completely bizarre. Why do a major, international elite arms force allow two pretty random soldiers to just join them? Sure, the main character (name genuinely already forgotten) has intel they need but he could provide them with it in a couple of hours, at most. Plus, the nature of that intel makes him instantly compromised from a security viewpoint! But oh well, it's not like the intel makes any sense, so perhaps the Colonel was just keeping him close to work out what the game plan was. I mean, the solider tasked with transporting the latest super-weapon is attacked by a previously unknown group of extremely advanced terrorists, who just happen to be lead by his ex-fiancée. Yeah, no way in hell is a trained military leader going to buy the "coincidence" line here. Especially considering the soldier's story is that they only broke up a few years back, at which time said terrorist leader was a homely soccer mom type who could barely cope with the knowledge here fiancée was going to war. Now, she's openly killing dozens of soldiers whilst wielding incredibly advanced technology and displaying a level of hand-to-hand combat skill that would take a lifetime to develop. But that all makes sense because... no, actually, forget explaining it. Maybe it's a side effect of her brain control injections... given to her by her brother... who she believes to be dead.
Yeah, you know what, I'm done here. This film is just stupid. Not bad, or ridiculous or garbage, just intellectually stunted to the point of pity. Don't bother, at all. If you want mindless violence framed around a beloved kids play-thing from the late 1900s, watch Battleship. At least that makes an attempt at humour, understands what it is and is vaguely entertaining.