Universal Sentinel 3: Homeworld ($2.99 -> Free): https://itunes.apple.com/us/app/sentinel-3-homeworld/id396103539?mt=8 Tractor Trails ($0.99 -> Free): https://itunes.apple.com/us/app/tractor-trails/id486348309?mt=8 iPhone Sentinel 2: Earth Defense ($0.99 -> Free): https://itunes.apple.com/us/app/sentinel-2-earth-defense/id320388936?mt=8 Space Station: Frontier ($0.99 -> Free): https://itunes.apple.com/us/app/space-station-frontier/id346227455?mt=8 iPad Space Station: Frontier HD ($2.99 -> Free): https://itunes.apple.com/us/app/space-station-frontier-hd/id368763113?mt=8 They're probably best known for the Sentinel TD games, but SS:F is a real hidden gem. Not sure why the original Sentinel wasn't included in the sale, maybe it hasn't been added yet...
