I want to make a mod that sets a game global time limit

I always found the fact of not having a time limit very unchallenging and unrealistic. Even more considering one can abuse of spam resting. This is why I wanted to impose a time limit on the game so you would get a game over if the game is not finished before that time limit. I think Prince of Persia got it right by implementing that feature.

Any help on how could I tweak the game data to make this happen in NEARINFINITY?

Regards