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