TigerCake is going to be some form of abstract styled first person shooter. May include some humor, so things aren't too serious.
It's the better machinegun. Fires two times faster. Maybe it will always fire 4 shots, and maybe every 20 shots it will need 1 Cell. It could be fired without the Cell, but it gets slower.
I was thinking some other weapons need 2 ammo types too. All this sort of weapons can be fired without having any of the secondary ammo type, but they will be less effective in some way: firerate, damage, projectile speed.