I meant to write empty array. Thanks for pointing that out.

• There is no random tests.
• A sample test for "objects without clues" would be useful.
• The "If an empty Object is given, the game can't be continued." is not really clear. What is an empty Object"?
• Using a special string value to indicate invalid input is arguably bad design. The "Game canelled!" state should be signalled in some better way.

Yes!!