marble nest seems to have 4 endings according the wiki,

ending 1, accept death in the intro

ending 2, ask for another try at the end of day 10 (this restarts the demo)

ending 3, (according to the wiki) accept death at the end of day 10 is an actual ending and boots us to the menu (i think thats wrong and this might be a 100% ending actually)

ending 4, finish the heart quest line, giving you additional dialogue with the bird that triggers a "true" ending

...

ending 1 is a bit of a joke for any% but could be fun

ending 2 isnt much of an ending

endings 2-4 are dependent on the game time to progress to 21:10 (i think?)

but finding the 2 infected npc's (requires lockpicks) sets the time to 18:00 in the evening (wonder if theres others)

besides the waiting between 18 to 21:10, the rest of the run is optimizations