I've looked, but I can't find any information on this. One review mentioned the fact that you need to save Dingo in the amount of time allotted, but it didn't say anything about what happens if you don't.
Unless I am misunderstanding ---- I played this 6 months ago and didn't know there's a time limit on finishing the game. I am sure I went over 4 hours since I was playing - replaying.
I just finished it and at the very start the hologram message thing makes it clear that you have a time limit of 1:40 to meet his demands.
Then on the alien planet he contacts you again and seems to show a time left, for me it was 10m and something left which approximately seems to fit in with the amount of time I have registered on Steam.
OK, update. I left the game running and nothing happened, but since the next time you see the countdown is at the end of the game I think it is likely that running out of time might only affects the ending.
Either that or the countdown pauses when you are snoozing or it has no effect at all.