Here is the full list of all 41 East Tower - there are Kurenai achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
You've unlocked all of the Achievements!
You've unlocked all of the CGs!
You found out what happened after Sakuya and Kuon beat the East Tower.
You got the Love Ending - Male (Aggressive).
You got the Love Ending - Female (Passive).
You got the Normal Ending!
You've cleared Stage 6 and done a good job!
You've cleared Stage 5 and done a good job!
You've cleared Stage 4 and done a good job!
You've cleared Stage 3 and done a good job!
You've cleared RE:Stage 1 and done a good job!
So that rabbit is actually...
You found out what happened after Sakuya and Takashi beat the East Tower.
You got the Love Ending - Female (Aggressive).
You got the Harem Ending - Aggressive!
So that dog is actually...
Being a woman suits me more.
You found out what happened after Sakuya and Akio beat the East Tower.
You got the Love Ending - Male (Passive).
He has finally opened his heart to me.
He has been reborn to be with me.
You've cleared the Chaos World and returned to the East Tower.
You've cleared the Chaos World - University 3rd Year!
So the Dream World is literally a "dream".
Being a man suits me more.
You've cleared the Chaos World - University 2nd Year!
You've cleared the Chaos World - University 1st Year!
You've cleared the Chaos World - Past!
The path to the chaos world is unlocked.
You got the Harem Ending - Passive!
The new game master has been born!
You've cleared Stage 6 and done an excellent job!
So that cat is actually...
You've cleared Stage 5 and done an excellent job!
You've cleared Stage 4 and done an excellent job!
You've cleared Stage 3 and done an excellent job!
You've cleared Stage 2 and done a excellent job!
You've cleared RE:Stage 1 and done a excellent job!
You got the Bad Ending!
You've cleared Stage 1 and done an excellent job!
You've cleared the Prologue!