Just finished creating this quick game idea. The idea itself is not that complex but it's surely hard to play the game. So, basically you'll be shown paintings(mostly old ones) and you have to guess the name of the painter. You get to see your stats, and a global leaderboard.

I didn't want user's to register for the game. But to store leaderboard data I had to implement signup. But it's only being used to create the leaderboard, nothing else.