Link to kiyumiyama's mylist It includes the GuerrillaCraft series and other series; there is no mylist specifically for the GuerrillaCraft series.
I was going to make some neat linking on the translation notes, but... I Failed. So yeah. even though I can link it here like this, I can't do the same in the translation note.
If anyone reading this understands japanese, go watch it. It's pretty cool. [Blatantly advertising because I like his videos. Ya.]
GuerrillaCraft!
Refers to the GuerrillaCraft single player series by kiyumiyama-san. The hat is also characteristic from that series. See comment section for Mylist link.