In Changed, there are five possible endings, though only the 'true' ending can actually be considered happy. Almost all of the bad endings can be obtained by not caring about Puro enough.
Ending 1: "Betrayed Ending"
How to obtain: Play on Easy Mode or don't show any (or enough) love and care to Puro before the end of the Aquatic Area.
- Puro will tell Colin that he needs a host to survive, and he will end up assimilating the latter as his new "host". If shown enough love on Easy Mode, he will transfur Colin so that he still has company. On Normal Mode he will instead tell him that he wants to go with Colin to the outside of the tower so that the two can be free.
Ending 2: "Experiment Ending"
How to obtain: Don't show enough love and care to Puro before being kidnapped by Dr. K.
- When Colin escapes from K's lab, he'll find Puro in a puddle with his mask cracked, and K will be there waiting. Colin will try to fight and avenge Puro, but will instead get knocked out and experimented on by the scientist. If Puro was shown enough love, both he and K will be found knocked out (but Colin will first think that they're both dead), though Puro soon wakes up and tells him that he's standing on his tail. He'll explain that the doctor hit his head on a locker and that he (Puro) lost consciousness after the short struggle.
Ending 3: "Leave"
- How to obtain: Successfully reach the end and decide to leave.
- Colin and Puro leave the lab despite Dr. K's protests. After leaving, Puro will announce success, but the human will not respond- Either because of unconsciousness or death. The player will also get an achievement whose icon depicts the sun, a lump, and a large cross (confirming that Colin has indeed succumbed to the virus.)
Ending 4: "Stay"
- How to obtain: Successfully reach the end and decide to stay.
- Puro will leave the tower without Colin, clearly heartbroken, though he does say that he will keep in contact with him. However, without a host, he's likely to die before Colin'll ever have a chance to leave the lab. It's implied that Colin loses contact with him.
Ending 5: "Can't Decide"
- How to obtain: Successfully reach the exit and press ESC or X when prompted to stay or leave.
Dr. K will comment on Colin's inability to decide and will offer up an alternative solution. He will offer Colin the same substance he administered to himself. Despite Puro's protests, Colin accepts this offer. The procedure takes several days. During Colin's period of unconsciousness, he has a nightmare about a skull-faced death chasing him, and at his first awakening, thinks that it followed him to the real world. It is immediately revealed to just be Puro. The player will be shown the changes to Colin's body and it becomes clear that the procedure was a success. K explains to Colin that Puro is now controlling a bio-bot, meaning that he no longer needs a new host and that his life expectancy is increased. Similar to the 'Leave' ending, Puro announces success after exiting the lab- But this time, the human responds, making this ending far more optimistic.