It's taken over seven years but GCE is now up to parity with GW's #Gorkamorka books (including the Digganob expansion pack)

It's effectively an open source reimplementation of the 1997 Games Workshop game Gorkamorka. In reality it's more of a ruleset that can be used to play Gorkamorka but can also be used for other settings and long term the plan is to make it compatible with even more rulesets (such as Shadow War: Armageddon).