Well first of all it seems easy enough to do. The concept sure is easy. Then you find that it's actually quite interesting and new to you. Then, perhaps most importantly for the addictive effect, is that making the moves and going from dieing to restarting the game is so fluent/quick that it's just long enough for you to think "ah, I'll do one more, this wont won't take long". That plus the fact that it's really not that easy to win made it highly addictive for me.