Events used a combination of time-based and item-based triggers. Spoilers for the entire game below:
Upon starting the game, you need to look at the diary, bible, crucifix, and door. The diary changes for the first time 10 seconds after having observed all the items. The next part is completely time-based. Just wait for 60 seconds without looking at the bed and dying and the diary will change once again. The last part is completely item-based. Looking at the bible and crucifix unlocks the door and changes the diary for the last time. It's also worth noting that the order you use the items does not matter.
Regarding the ending of the game, it technically ends when you observe the door and see that it can be opened again. I originally wanted to play an animation of the woman leaving the room, but I ran out of time. The "I love you" message is not necessary for completion. It's just an optional observation you can make.
Anyways, thank you for all the kind words! I'm glad you enjoyed it!