Building a game like Angry Birds, and you are making something that scales. It’s pretty easy to imagine a level generating algorithm. You need random stackings of blocks, some pigs, and a selection of birds as ammo.
Making a game like Birdcage 2, it’s not likely a level generator can be made without every level feeling the same, which defeats the point.
I don’t play many games anymore, but I recently was reminded about both of these and thought it might be worth mentioning.
While Angry Birds no doubt makes more money, Birdcage 2 is infinitely more fun for me. To make an impact, sometimes doing things that don’t scale is a necessity.