Just one thing (i've been busy with classes this week) from early in the thread:
Whether or not a given game engine's mechanics (not the words but the processes themselves) can be protected by copyright has never actually been openly tested in open court. Whilst the rules of copyright do not explicitly protect rules, and in fact exclude processes explicitly, they do cover derivative works. Proving derivation could easily be attempted by showing the identical processes in use.
Also, trademark law covers look and feel... similar enough is in fact trademark violation, and trademark, like copyright, need not be registered to be defended.
Further, a process CAN be patented. I know of no patent protected RPG's, but several board games have protected their rules with patents in the past; such patents do expire, and are not renewable, so they're less protection...
Whether or not a given game engine's mechanics (not the words but the processes themselves) can be protected by copyright has never actually been openly tested in open court. Whilst the rules of copyright do not explicitly protect rules, and in fact exclude processes explicitly, they do cover derivative works. Proving derivation could easily be attempted by showing the identical processes in use.
Also, trademark law covers look and feel... similar enough is in fact trademark violation, and trademark, like copyright, need not be registered to be defended.
Further, a process CAN be patented. I know of no patent protected RPG's, but several board games have protected their rules with patents in the past; such patents do expire, and are not renewable, so they're less protection...