Thanks to a heads-up from CBM's own, TheBlackWidow (aka, Twitter's @Zarina_Romanoff) we have the following spoilers which were posted on the SHH Forums by "protocida". As usual, take something like this with a huge grain of salt, but they certainly fit in with what we've heard before and as I'm sure you'll agree, sound pretty damned amazing!
WARNING: MAJOR SPOILERS AHEAD!
-The Star Sapphire crystal will appear.
-There's a reference to "the prophecy" in the Book of Oa. Probably refering to the war between the Green Lantern Corps and the Sinestro Corps.
-The ring speaks. When Hal first uses it, it says "Voice signature identified. Willpower registed. Ring online."
-Kilowog's power ring makes a cannon-like "BOOM" sound, like in the comic books.
-Hal's constructs include a gattling gun, a giant green hand, a dune buggy, an anti-aircraft gun, a F-18 jet, a sword, giant pulleys and much more.
-Sinestro's trademark weapon is a double-edged Korugarian spear. He also makes a construct of Kilowog at one point.
-The Guardians live in high towers near the Great Hall of Oa. Krona's tower is slightly toppled as a sign of his corruption at Parallax's hands.
-During a battle scene, Hal's and Sinestro's power ring run out of energy, and Sinestro tells Hal to summon his battery from the pocket dimension. Hal says he doesn't know how to do it, and Sinestro asks him if Kilowog never taught him that. Hal says no and Sinestro gruffs before him and Hal unite their rings, opening a small wormhole from where Sinestro pulls his battery. Him and Hal both recharge on it. This is taken almost word-by-word from Geoff Johns' "Secret Origin.
-During the final battle, Parallax tries to possess Hal, but fails. In the process, Hal has a vision of the future, where Coast City has been destroyed and he is the one to blame.
-Hector Hammond tries to steal Hal Jordan's power ring, believing that it can cure his mutation, just as Parallax arrives. It consumes Hammond and tries to use the ring's energy, but fails and then tries to use Hal as a weapon to tap into the nearly unlimited powers of the Green Light of Willpower.
With an all star cast which includes Ryan Reynolds as Hal Jordan, Blake Lively as Carol Ferris and Mark Strong as Sinestro, director Martin Campbell's
Green Lantern is set to be released in 3D on June 17, later this year!