I pulled this directly from the steam page...
1) Create Unique Creations - On purchase, you receive 20,000 graphic files, we are still developing much more.
2) License - Use the Steam IGB Package for your game, web, print, or other commercial development project. All assets are royalty free, no hidden costs.
3) New Content - Content evolves depending on support. Get us to work on what you specifically want.
4) Full Access - You may edit, manipulate, and change the graphics in any way for use with your game development. Some Photoshop files included.
Included Assets: (take note that these may be added onto)
*Newer - Icon Creation Kit
*Newer - Tank Creation Kit
*New - Animated Character Creator Pack
*New - Animated Bug Invaders & colorful planets
Interface Builder (5 styles)
Jungle Scene and Platform
Map Maker (5 styles)
Ship Builder (29 styles)
Solar System 2
Top Down Landscape
Weapon Builder future
Weapon Builder modern
Weapon Builder medieval