Honestly unless there are some fantastic stock internals, this whole blaster looks pretty redundant. Basically everyone has a maverick already or can get one for pretty cheap, and there really isn't a point to having a stock and extendable barrel on a pistol. Of all the new releases coming out at the end of the Summer, this is the least imaginative design I've seen.
A 12-dart clip would've looked pretty cool, but 18 seems like serious overkill. The clip shouldn't ever be longer than the gun (unless the gun was semi-auto, which would be ball-blastingly awesome and will never happen).