How To Judge Legal Risk When Making a Game Clone?

An anonymous reader writes
"I'm an indie game developer making a clone of a rather obscure old game. Gameplay in my clone is very similar to the old game, and my clone even has a very similar name because I want to attract fans of the original. The original game has no trademark or software patent associated with it, and my clone isn't infringing on the original's copyright in any way (all the programming and artwork is original), but nevertheless I'm still worried about the possibility of running afoul of a look and feel lawsuit or something similar. How do I make sure I'm legally in the clear without hiring an expensive lawyer that my indie developer budget can't afford?"

http://games.slashdot.org/story/10/0...g-a-Game-Clone