For a movie that's about a superhero that I'd have to say isn't the most popular, or well known among the general public, you really have to make sure you explain everything well and have a compelling story. They attempt to explain the entire Green Lantern history to you in the first few minutes, but it's all too quick and neat. They just tell you what happened instead of showing you what happened. If you're just going to tell the story through narration and voiceover, then why make a movie about it? I can read the backstory myself. It kind of defeats the whole point of making a movie about it.
My main complaint about this is the same complaint I had about Kill The Irishman: They try to tell too much story in a short period of time. It seems like there were sequences and relationships that should have been fleshed out much more, especially when he reaches the planet Oa and the character of Sinestro. These scenes are way too short. With a runtime of only 1 hour and 45 min, they could have made this a bit longer and taken the time to explain things better.
If they want to make this a trilogy, it seems they could have done a better job of setting up relationships and characters. It's like they needed to watch X-Men: First Class to see how they should have done this.
The performances and cast were all fine, they just aren't given that much to work with. I'd have to say that I didn't like the character of Hal Jordan all that much. Again, I don't really blame that on Ryan Reynolds, as I just don't think the character is written that well. Maybe that's how he's supposed to be in the comics? I don't know.
For example, after training with the Green Lanterns for only like five minutes, he just goes, "Being a Green Lantern is hard! I quit!", and he just goes home. Plus, they just let him keep the ring. If this ring is supposed to be so powerful and this is first human that's been given the opportunity, you would think they'd make him give the ring back. "Hey, if you're going to quit like a bitch, then you can just give that ring back, human!"
Plus, the villain is just not interesting or compelling. When the climatic battle scene finally happens, you just don't care and it resolves without much difficulty even. It wraps up too neatly to the point where I was like, "Oh, that was convenient."
During the credits there's a reveal that really only makes sense at all to people that have read the comics. If you haven't read them, you see the reveal and are just like, "Um, okay. That seems kind of out of nowhere." It's just not setup well at all.
The effects aren't bad. The clearly put some money into it, but when the power of Green Lantern ring is to make anything the wearer can think of, you'd think they'd be a little more imaginative with it.
As for the 3D, it doesn't do anything for this one. In the theater I saw it in, the 3D was so dark that several times I took the glasses off in order to see better. I just wasn't impressed at all by it.
It's not an awful movie, it's just 'blah'. The whole thing just kind of a 'TV movie' feel to me. Nothing really excited me, made me laugh, or kept me interested. It was missing all of the things that have been in the movies I've enjoyed so far this summer.
I really don't recommend seeing this in the theater. Wait for video and hopefully they'll release a extended or director's cut by then.