Bitcoin Gold is the brainchild of Jack Liao and is launching as a hard fork of Bitcoin. The goal of BTG is to become a better gold than Bitcoin. The chief way they have decided to do this is trying to solve miner centralization through a proof-of-work change.
Changing proof-of-work is generally going to require a hard fork and BTG has decided to go that route. The proof-of-work that they’ve chosen is Equihash, a memory-hard algorithm that’s fairly ASIC resistant and also used by ZCash. The idea is to give mining back to the users who can start using CPUs and GPUs to mine.
BTG developers are also considering a premine of up to 1%. How that will be executed is unclear, but will probably consist of taking some of the mining reward as they’re committed to keeping BTG at the 21 million limit