In Japanese version, this stage takes place in Saga Prefecture. In the Taiwanese version, stage 2 is set in Hong Kong and Mongolia appears later as stage 5.
Mongolia's base is a yurt (also called a ger), a kind of portable tent used by nomads in Mongolia, Siberia and Turkey.
The elderly woman on Saga Prefecture's base is a reference to Saga no Gabai Baachan (Gabai Granny from Saga), a series of novels written by Shimada YÅshichi based on his childhood growing up with his grandmother in Saga. The woman's stance and attire suggest that it is specifically the movie adaptation being referenced.
Prior to version 11.7, there were 4 extra Snaches which spawned after bringing the enemy base down to 50% HP, with a delay of 1-2 seconds between each Snache.