The developers describe the content like this:

This Game may contain content not appropriate for all ages, or may not be appropriate for viewing at work: Frequent Violence or Gore, General Mature Content

First, save the world in the most violent way possible.

Then have a look behind the scenes on how the Apocalypse was designed, take the music of God's Trigger with you on the road, and spruce up your desktop with some cool world-saving art.

The God's Trigger - O.M.G Edition comes with:
-God's Trigger (obviously)
-Artbook with more than 70 pages of character drawings and level design concepts (some pretty cool stuff there!)
-Original soundtrack with over 40 minutes of music from the game in mp3 and lossless FLAC formats (vinyl is still TBA)
-10 high-resolution wallpapers with art from the game (because there's no such thing as too much cool art)
-A short digital comic book (for those who like art AND story)

When an Angel and a Demon team up to kill their way into Heaven and stop the apocalypse, bullets will fly and blood will be shed.

Play solo or in with a friend and burst through a room in a matter seconds killing enemies with a bucketload of weapons, special abilities, and melee options in a show of blood and explosions!

Kill enemies in the most graphic way possible!
Make split-second decisions, dodge bullets and inflict violence in a highly stylized, fast-paced bloodbath.

Each character brings their own unique powers. With a treasure trove of weapons and customizable special abilities you have the means to annihilate your enemies in just the way you like.

Two heroes working together will slay enemies twice as fast! Switch freely between Harry and Judy, the Angel and the Demon, at any moment in solo mode, or grab a friend and work together in co-op for even greater bloodshed!