WorldCraft : 3D Build & Craft is a free block-based game of exploration, crafting and survival in a world visualized through simple retro graphics. If that sounds familiar, you're not wrong: this is very much a mobile Minecraft clone. It allows players to choose between a single-player "survival" mode in which enemies pose a hazard or a "creative" mode which is more of a sandbox game. Multiplayer mode features pre-created worlds and a chance to interact with other players.
Translating a hit to the small screen
WorldCraft : 3D Build & Craft attempts to bring Minecraft-style gameplay to mobile devices, and it mostly succeeds, taking advantage of the fact that the game it's emulating has relatively simple controls and graphics. There are even some clever improvements, like the addition of a "cautious" mode that automatically prevents you from falling and dying while moving around the world (although it does mean you can't walk down a flight of stairs). Some of the mechanics are less polished -- combat results can often be a little unclear, for instance.
A work in progress
WorldCraft : 3D Build & Craft is an engaging attempt to bring a classic PC game to a mobile device, even if it is imperfect in places. There are a few rough edges, and the difficulty may be a little high, but if you like crafting games it's worth a look.