I'm not sure I'd be entirely at home in a cube world, seeing as I'm completely spherical, but you may fare better in Picroma's long-awaited procedurally generated sandbox RPG Cube World (opens in new tab) , which is essentially what happens when you put Minecraft, Zelda and World of Warcraft into a blender - before putting it to one aside and getting a talented developer to make a similar game instead. Well, Cube World now has an alpha version that you can pay money to play - if you're lucky enough to be able to access the shop. Picroma are currently having a bit of intermittent trouble (opens in new tab) thanks to a) the game's immense popularity, and b) regular denial-of-service attacks.
If you manage to get in - Picroma are having to "disable user registrations and the shop from time to time" - you'll be greeted by a game that seems to include every modern gaming trend: a sandbox, crafting, voxels, procedural generation, pets and probably zombies too (feel free to correct me on that). There are many, many more details in this informative blog post (opens in new tab) .
If you're wondering whether Cube World will run on your Amiga (it won't), your sorta good PC or your much less good laptop, try this mini demo (opens in new tab) . The following video offers a good look at the game as it stood a couple of months ago.