Microcraft is something of an oddity. It's a fan-made "remake" of a port of a Notch-made knockoff of one of the most popular indie games of all time. Wow, that was intense.
The game itself functions much like a top-down Minecraft, with a few other key differences. While surviving assaults by vicious monsters and crafting items from wood and stone are still a major factor, there's not much in the way of building. So while players can (and should) explore the world and create helpful tools and weapons for themselves, they can't construct a fortress to live in. Kind of a shame, but making something like that from this perspective would undoubtedly be tough to pull off.
With several "mobs" to fight, a number of different environments to explore and a day/night cycle (not to mention all the crafting), I think Microcraft should make for a good time. Whether or not it stays on the App Store for very long is up in the air at this point since it does share many a similarity to Mojang's runaway train of a game, as well as Notch's Ludum Dare spin-off, but I'd like to think that it's different enough to earn a permanent place among the other hundreds of thousands of titles up there.