There is a case building for a Shared Example that all games run to make sure they provide some common behavior.  This serves as protection when you start adding stuff to individual games to make sure they don't unintentionally break something.

You currently have a spec for Game that is not really legit and an empty spec for the IDoubtItGame.  You should probable migrate the game_spec to a shared example and use it in both i_doubt_it_game_spec and crazy_eights_game_spec to use them

See https://www.relishapp.com/rspec/rspec-core/docs/example-groups/shared-examples