How possible is a minecraft-like game, or really any other 3d game?

Don't, we'll summon more 10 year olds than we already have

Its possible, but it will be very very slow without heavy optimization and tricks. Id be surprised if anyone could make a 3d procedural world but i have many doubts.

it would really be better to have a perspective projection function and 512 sprites on the upper screen. Put all of the sprites in a SPFUNC and CALL SPRITE