There will be 2 new game modes in Counterstrike Global Offensive game. The first one is called Arsenal: Demolition and the second one Arsenal: Arms Race. These 2 new game modes in csgo will be developed by the original creators of GunGame mod for Counter-Strike: Source.
Valve team is working on this closely with GunGame mod creators to have 8 new maps in the 2 Arsenal modes with the original feel of the mod. Valve is known to support and live through its dedicated community after all! Most of their employees are known to be past fans of their games that made mods for them! Long Live Valve (+ Steam)!
Watch the whole new screenshots from Arsenal game mode in CS:GO bellow.