We started our journey with the German adaptation of Skat. The idea was to build an evergreen mobile game for a niche. I just had read the Tim Ferris book 4 hour work week ;)
We also built:
Run Forest Run, Easter Eggs, Flight School, Lost Treasure, Eurovernichter and maybe a few more i forgot :)
see https://leifgriga.com/SmartphoneGames/index.html
When the iPad came out we also thought that maybe local multiplayer social games will be a thing. Therefore we invented this category with Zombie Party - see here.
Here are more cool videos from our projects at MobileBits https://www.youtube.com/watch?v=NNSFrBgGsOs
MobileBits n-TV Homestory: https://www.youtube.com/watch?v=-_HztO9RUok