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