Saiko no Sutoka
Don’t give yandere girls any reason for jealousy. Ideally, always stay in their sight, talk only to them, and ride them on your back. That is what Saiko wants you to do in this game, and if you don’t obey, you’ll have a badly bad time.
To escape the school, you need to find a password to the principal’s safe and take the key. But your sweet princess always stands a few steps away. She will play with you and pierce you out of excitement. Alternatively, she can poison you with gas and watch you die slowly. If you don’t want to stay with the cracked girl forever, never let her close!