I was just starting to work on my new puzzle/survival game and just figured to share my story which I think could be interesting. You are created with a mission that somewhere far away there are standing dominos that needs to be hit and fall on the side (chain reaction). You was just being delivered to the place and get lost from the others. The main mission at first is to reach the ceremony in which you need to hit the first domino. You encounter obstacles and need to stay standing, because if you fall on the side you are dead(/or incapable of continue your mission). Then you get to the ceremony where everyone is waiting to do your thing and start the domino reaction in which case you would die. You don't listen and continue your new mission: survive. That means encounter angry characters that created you. I choose letter "i" because I wanted to make more puzzle variety, the dot on the top can hold the whole character, so you can use flat environment to go over ledges. All of the other characters are also easy to fall, so you can fight with them if you are higher. The biggest enemy for you is uneven ground of course. I just can't decide if domino blocks are persons too, because that would be very evil ritual to make them stand in line and then hit them. That would be the basic story. It would be nice to hear your thoughts about it.

Do fallen dominoes disappear? What places or resets the dominoes?

No, dominoes don't disappear, generally they just wouldn't able to move. It would be like a fish that couldn't swim. Maybe they die more physically, maybe from the thought that they are useless for others. They would just become an obstacle for others trying to walk.
The world consists of tall figures that are easy to fall. The normal proportions for their base would be 1 on 1 and as tall as they become. So dominoes would look very different from others: they are very long to one sides. That would make others angry and maybe someone thought to destroy them in an ritual so they created you. And since you don't obey, you are thought to be an ally of dominoes so everyone is against you.

I wasn't thinking much about how and why, because at first I wanted to create a puzzle game and just later figured out some story concepts that would make a reason why you are going somewhere after all. Maybe later they could encounter some sphere characters that would have advantages against them, but I'm now focusing more on the game itself that isn't very long.