I believe there are 4 win screens, they appear after the end credits.
1. Complete the game
2. Complete the game with 100%
3. Complete the game with 100% under a 2 hours
4. Complete the game under 1.5 hours
I managed to get the first 2, I finished the game in just over 2 hours.
I did another 100% run in just over an hour and a half and unlocked the third ending and then a 75% run straight after finishing at just over an hour and unlocked thee forth, so I can confirm these times.
Comment your times and what screens you unlocked :).