Kakyūsei 2 inspired an all-ages TV anime in 2004, the adult Kakyūsei 2: Anthology OVA in 2006, and the adult Kakyūsei 2: Sketchbook OVA in 2007.
The first game inspired the End of Summer four-episode OVA in 1994 and the adult Dōkyūsei: Climax OVA in 1995.
Kakyūsei inspired the Elf ban Kakyūsei (literally “Elf-version Kakyūsei,” the title distinguishes the anime from the similarly titled but unrelated OVA by Pink Pineapple) four-episode OVA in 1997 (only the last episode has adult content), and an all-ages TV anime in 1999.
Dōkyūsei inspired a 12-episode adult OVA 1996 (this was also aired on TV in Japan with the adult scenes removed), and the Dōkyūsei 2 Special: Sotsugyōsei OVA in 1999.