2. The second age-old strategy is intuitiveness. This is different from simplicity; Candy Crush — or even Minesweeper — isn’t “simple.” But after you play it for a bit, you intuit the rules. Games that go viral don’t need massive instruction manuals or help files; users intuitively grasp the rules.
3. Finally, games that go viral have a recognizable storyline. Save the girl. Beat the bad guy. Claim the trophy. When a user succeeds in a viral game, he doesn’t do so only on a virtual basis; he can also relate his success to a real-world counterpart.