Space Miner: Space Ore or Bust is on sale for $1.99 - totally worth it, imo. It's basically Asteroids mixed with an RPG but it's completely addicitive. I just keep going back to it time and time again so I can upgrade my ship even further.
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And I may be a humongous cigarillo but I can't help but love the Virtual Villagers games (2, and 3 especially). It's like animal crossing/The Sims combined with an ant farm fused with Survivor. You don't have real control over your people on the island but you can eventually make them learn behaviors like becoming builders, scientists, farmers, doctors, etc. and they can mate to expand your population but you have to figure out ways to create sustainable food sources, housing, researching technology, etc. to allow them to live, if not they die. They'll kick the bucket either from old age, accidents, famine, disease, etc. so you have to keep going back to it time and time again to check up on the people 'cause it runs in the background all the time regardless if you're playing it or not. Plus there's a series of goals and mysteries you have to solve and or perform to "win" the game so it's not all completely pointless. IMO, the VV games are the best bang for the buck on the entire iTunes store.
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