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