The problem with that is people don't care about clones, they care about quality. If you love tower defense games you are going to love a heap of them that are

The problem with that is people don't care about clones, they care about quality. If you love tower defense games you are going to love a heap of them that are more similar than different. If you love physics puzzle games then there's a virtual orgy of same-games out there waiting for you (eg http://physicsgames.net/ http://physicsgames.net/ ... there's like 3 or 4 games there, done dozens of times). All Zynga has to do is get a same-game in the charts or viral and they get new users.