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