Here is the full list of all 19 Doki Doki Literature Club Plus! achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Start a New Game.
Spend enough time during the poem minigame for the music to loop.
Write a perfect poem for Sayori.
Write a perfect poem for Natsuki.
Write a perfect poem for Yuri.
Write a perfect poem for Monika.
Finish all of the Side Stories.
Achieve 100% data collection.
Love, Monika
Find Dan's special note.
Write a poem in 20 seconds or less.
Listen to a lot of what Monika has to say.
Draw boxes on the desktop.
Your desktop wallpaper could not be changed due to an administrative policy restriction on this computer. For more information, contact your system administrator.
Ruin the game.
Choose not to quit DDLC.
Spend 20 minutes listening to music on the desktop.
Review Paula's project plan.
Delete Monika twice while getting deleted zero times.