I think one game can be core or casual depending on the player...
Ex : - Mario Kart 8 can be played casually with daddy, granny and the little cousin. However, I doubt you can beat the world record on any track without playing hardcore.
- You can complete Hyrule Warriors legend mode in 10h and be done with it or sink 150h+ in adventure mode to get everything.
Overall, my definition would be : trying to get everything you can from games you buy. And I think one person can play some games casually and some games hardcore...








