Rotten

If not the game play, the lore will get you hooked. vise versa. The games lore isn't even 100% done with multiple games and you can see each piece with each game, seeing the once active Izalith area in ds1, all run down and collapsed in ds3. Things like that are just so amazing to see. Not a lot of games have their series linked like this one. Controls are easy to learn, bosses are an incredible challenge and once you've played enough, you can destroy each boss after they wiped the floor with you, giving you a feeling of power. And then you can also say to your friends who may just be starting ds much later "I can just kill the boss for you" earning you bragging rights ;)