Here is the full list of all 15 Kinkoi: Golden Loveriche achievements.
Unlock the Hidden Special End
Unlock all Achievements
Reach the True End
Finish Ria's Route
Finish Sylvia's Route
Start Ria's Route
Start Sylvia's Route
Finish Elle's Route
Start Elle's Route
Finish Akane's Route
Start Akane's Route
Finish Reina's Route
Start Reina's Route
Finish Common Route
Start a new game