Like this artist a lot. I would suggest playing his game instead of going through all the CG here immediately though, as they're much more impactful with the setup and story behind them!
The artist actually does not permit sharing of the cgs though, as he prefers people to play his game since quite a lot of effort was put into it. I hope you would respect his wishes and contact him directly regarding this. Here is his Twitter if anyone is interested: https://mobile.twitter.com/nyagato2?lang=en
@xElemental I don't think GT2 has been updated recently but from some of the new images that look like backgrounds, it seems like this gallery has been ripped from the game rather than it being the gallery in which nyagato has attached with the final version. (Accessible upon completing the game)
@xElemental It's been a while since I played it but if I can recall, you need to beat the 2nd last boss fight aka the one with the 3 mechs and don't go to the last boss immediately, instead sidetrack to one of the areas that you may have gone previously, it has a few islands and a city at the end, that area has submarines too. If you visited this place when you were smaller and didn't finish the mech boss fight yet, the protag will indicate that you can come back when you are bigger as the wall surrounding the city is too high or something. Hope this helps