Here is the full list of all 37 Gal*Gun 2 achievements.
Unlock all other achievements.
Reach the Harem ending.
Get every girls' phone number.
Reach Risu's good ending.
Finish Chiru's route B.
Finish Nanako's route A.
Upgrade your Pheromone Goggles to their final form.
Upgrade your Demon Sweeper to its final form.
Finish Nanako's route B.
Take a good look from below when you have a girl over.
Call a girl over to your house for the first time.
Get stepped on by 50 girls.
Get stepped on by 10 girls.
Get kissed by 50 girls.
Get kissed by 10 girls.
Give 500 girls euphoria.
Clear all of the Kamizono Sisters' requests.
Have plenty of conversations with Nanako.
Reach the ending for the first time.
Finish Chiru's route A.
Give 30 girls Striphoria.
Clear your first Doki Dokie Mode.
Clear your first search mission.
Use the Demon Sweeper to give a girl Striphoria for the first time.
Suck up 500 mini-demons.
Give 50 girls euphoria with Lovestrikes.
Have plenty of conversations with Chiru.
Give a girl a snack for the first time.
Suck up a Metal Kurona for the first time.
Clear your first defense mission.
Suck up 100 mini-demons.
Give 100 girls euphoria.
Get 50 ecstacy shots in a row.
Get 30 ecstacy shots in a row.
Clear your first regular mission.
Perform a Lovestrike for the first time.
Get an ecstacy shot for the first time.