So, I bought one of the Toa:Phantoka sets today, and started playing with this blaster. The blaster seems to be a revamped version of the Zamor sphere launchers. I do prefer this version.
It is a neat design, but it doesn't really have a handle or range. I eventually plan on adding a better spring, but for now a handle will have to do.
It's really quite comfortable.
In response to user questions, the round bit that sticks out on the bottom is the handle. This makes it easier to hold in the classic 'bang-bang' shooting position. To fire the pistol, you pull n the little tab in front that my finger is resting upon.