Here is the full list of all 33 Re:Kuroi Demo achievements.
Stage3 Clear
Stage2 Clear
Stage1 Clear
All Stage Clear
Stage4 Clear
Stage5 Clear
Stage6 Clear
Stage7 Clear
Stage8 Clear
Stage9 Clear
Stage10 Clear
Stage11 Clear
Stage12 Clear
Stage13 Clear
Stage14 Clear
Stage15 Clear
Stage16 Clear
Stage17 Clear
Stage18 Clear
Stage19 Clear
Stage20 Clear
Fire Magic Master
Thunder Magic Master
Ice Magic Master
White Magic Master
Black Magic Master
All Magic Master
All Actor LvMax
EnemyInfo Master
All MagicExp Max
Challenge Master
All Achievement Clear
Quiz Master