Here is the guide for all four endings.
Bad Ending (Extinction)
1. Get the seeds of the first room.
2. Go on the balcony.
The Good Ending (Friends)
1. Get the seeds
2. Click on the rat trap located in the kitchen.
4. Get in the bedroom and back into the kichten.Grab the dead Rat.
5. Go on the balcony.
Passive Ending (Unforgiven)
1. Get seeds from the first room.
2. Click on the picture in the first room and then on the clock.
3. Change the time to 12:00. (Flashback)
4. Go to the balcony. Done.
Aggressive Ending (Venomous)
1. Get seeds.
2. Get the rat (click on the trap in the kitchen, walk to the bedroom and go back in the kitchen.)
3. Go back to the first room,enter the door and then in the dirty toilet/bathroom whatever. Click on the mirror and grab the needle.
4. Go out of the room go in the storage. Click on the Ink. He will poison the rat.
5. Go out on the balcony. Done.