Let me tell you about my life a little over a decade ago. I bought a PC strategy game called Hegemonia (AKA Haegemonia) on a whim in 2002. I played the campaign mode of that game no fewer than four times. It was fantastic. Now it's on Android, and this may be the last you hear from me until early next year. That is, of course, assuming it's still fun to play on Android.
Haegemonia is a 3D space RTS that places you in command of massive warships and nimble fighters. The story begins as a simple internal struggle for power in the solar system as Mars fights for independence, but then an alien force descends, seeking to conquer and enslave humanity. It has been 10 years since I played the PC version of Haegemonia, but I do seem to remember the story being quite interesting. There was a single standalone expansion to the original PC version, but I'm not sure if that's included here.
The graphics for the time were excellent, and they still look pretty good on Android. The texture resolution might not be as good as some of the simpler on-rails experiences on mobile devices, but there's a lot going on in Haegemonia. Some of the controls have been spread out on the screen, but it uses multitouch for most of the common game interactions.
There are two listings for the game—one for $3.99 with the full game, and another that lets you play the first four missions free, then pay $3.99 to unlock everything else. Note, the paid version seems to list in-app purchases, but I think that's a mistake.