As long as you write your own code and make your own graphics you should be allowed to create whatever you want. In this case, "Imitation is the sincerest form of flattery" fits perfectly. Copying someone elses work also increases competition which is good for everyone, especially the gamers.

I can distinguish it, but don't really care.

A good game is a good game regardless of who wrote it, or who came up with the original idea. The logo on the box is unimportant.