... is it 100% gpu resistant?
Nothing is 100% GPU (or even ASIC) resistant. It's just a matter of effort and money whether someone will succeed in creating a GPU miner.
Our approach with ZETTEL and its constantly evolving "Burgerhash" algorithm is that every 100k blocks (ca 10 weeks) we are
increasing the complexity of the POW algorithm,
so that any hypothetical GPU-miners (should they come into existence) become
obsolete.
This is what supporters need to understand, that there is no 100% GPU/ASIC resistant. If it is profitable enough, engineers can build ASICs in secret and mine in secret. It's up to the developers to continuously innovate to make their coin GPU or ASIC resistant.