I am about to solve one of the great mysteries of life for you. One of those unsolvable questions of gamer life has just been given an answer and I am going to let you guys and girls in on it. Ready?
What defines a game as hardcore? What defines a game as casual?
Nothing. It's the player you define as hardcore or casual and how far they are willing to take the game.
Take this for example. My mom fucking loves Zoo World on Facebook. If she isn't working, she is playing Zoo World. She is hardcore about this game. He has three different browsers open, she has spreadsheets going for what kind of animals to breed, she works with people on Facebook to find exploits to get unlimited animals, she has Firefox open with 20 tabs refreshing over and over to multiply her zoo worth. It's insane. I hate it. It lags the whole house internet and I can't play Bad Company 2. She is hardcore about that game.
I play Halo 3 occasionally. I have all the map packs, but I still only boot it up once every few weeks. My rank is always reset back to 1 when I play. It's an easy game for me to just jump into and shoot the shit (literally) and have fun. I don't have a problem with this. Halo 3 isn't a game I plan to play for hour and hour and hour. It's just a game I bought because it was the multiplayer game to own for 360. I am really casual about playing Halo 3.
You can't really define a game as "casual" or "hardcore". Anyone can play any game. It's just how much a person is willing to take said game. SHMUP's can be played by anyone. The hardcore players will be finishing it in one credit without dieing. Anyone can play Demon's Souls, but if you're me then you can run through the game blindfolded knowing all the exploits and tricks. Sure, people will sit around on Facebook and play Farmville or Zoo World just to occupy time, but it's a person like my mom who take it to the next level. It's not about the game, it's about the player.
And personally, I think it always should have been thought like that.