This is one of the missing weapons in blockland mods. Its the Half-Life 1 Tau Cannon!

There is a primary fire and secondary fire.
Primary: Fire rapidly the Tau Cannon using 2 ammo per shot.
Secondary:Charge up the Tau Cannon shot,using up to 10/13 ammo.
There are preferences.
Higher Charge/Lower Capacity:When turned on,the tau cannon uses 10 ammo and charges faster.
Tau Jumping: When checked,you can use the recoil of the gun to Tau Jump.
Vertical Tau Jumps: When checked,you can Tau Jump vertically.
The gun uses an ammo system. Using boxes of Depleted Uranium-235.