I get the idea, it's nice that it exist, goblins need more love. Literally and figuratively.
That said i'm a pretty fast reader and all 4 routes took me 13 minutes combined, so i have no idea where overview got 15-20 per route.
The writing is not awful or anything but it's so incredibly little it ends before you even start enjoying it, all 4 "routes" are just super short brainless instant sex encounters with strangers. I only give it 2 for relatively rare goblin thematic combined with pretty nice art.
If every encounter was actually a short story and not just a porn short i think it would be at least somewhat interesting, as it is i didn't find it engaging at all.