Terraria
PC/Steam Review

This game is a prime example that a game doesn't have to have good graphics to be enjoyable. When you create a world, the map is generated at random (aside from the guidelines you set upon creation). The game is easier to get into than Minecraft because you don't have to guess schematics on items you create; if you have the materials for an item, it will show provided you are at the right workstation. The fact that the world is randomly generated means that any given world will never be the same (unless you decide to send your map to your friends from saved files). This game has one of the highest replay factors of any game out there. The downside is that the developers have cut production on this game & no more updates will be getting released for it. The game also has multiplayer abilities, but there is unfortunately no server browser; you can only join a server via direct IP.