That was very interesting game!
At first I was able to somehow just dodge around the people and yoink that emerald, then I realized that I could shoot the walls but not the people, and at that moment it has opened up to more strats that you can pull off & the game has gotten far more interesting because of it.
I think the fact that the emerald stays at the same spot can be improved by doing what the others have said; by making the emerald spawn in the random locations. If you take that idea and go further and maybe procedurally generate the levels plus do some balance & gameplay adjustments, then I think this can potentially turn into some sort of fun procedurally-generated-roguelite-heist simulator! I can smell the potench' from that aspects of this entry.
Overally, it was quite interesting idea and I can see some potentials for making this into a full game.