I had this idea also, but the problem was how to get it to work in a 3D world.
I got an idea, do you know games like Minecraft, rust ... Where you have to loot object?
You can loot different objects to get primitive resources like trees, stones, animals.
My idea is:
When a user wants to loot stones, at that moment, he is also verifying block hashes aka "mining". The problem with that is if the block creation frequency is too high, let's say 10 min like bitcoin, in-game being with a peak hitting at a rock it would take the user a lot, and not having into account the difficulty.
So, you could create different types of "stones", with different resources inside, metal, gold, copper, etc, so and depending on the type in-game it would be more or less difficult to loot this item, that would somehow represent the time&difficulty to mine a block in the chain.
But anyway, that's not a solution cause the incrementing difficulty, so another idea for that is, to keep a record of who has looted objects, what type of object, and for how long ingame, and when a block is created that will be taken into account, let's say:
Block #500 reward(10btc)
User 1: looted 500 stones of gold (gold would be the most difficult item to mine), he would receive, let's say 80% of the block reward.
User 2: looted 800 stones (just stones) (easiest) would receive 20%.
So that could be an idea.
PD: The question is not "if it would be possible to implement it" because actually, it is. The question would be, what kind of product you want, what type of game, is it worth all the effort and cost, will it be rentable? will it have a market?
Anything is possible in the software world, but as stated before, your question is not correct.
The problem I see with this mining mechanism is that your cryptocurrency won't be transparent, what I mean with that is that to mine a Block you have to play.
Also a fun idea.. But you dont need it to work in a 3D world, you just need to hash the game and embed it in bitcoin or ethereums blockchain so everyone play by the same rules.. And then it just have to read to scoreboard after each round..