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