I'm following up here based on a brief conversation on Twitter between myself and Chris Gonnerman wherein I was looking for information / guide posts for creating an open clone of a product and Chris very kindly offered to share his knowledge on the condition we do it here so it's publicly available for other folks.
The TLDR on my end is that there's a game I want to hack, use as the base for some of my own work, and otherwise mod. All well and good except it's a wargame with no license for use, only copyright. So my thought is to do an open clone of the system, stripping out all the author's wonderful insights, writing style, art, etc to reassemble the engine - recognizable, but not infringing (as best I can).
I don't know how this has been done in the past and haven't seen good resources for it despite some googling, so I figure going to the source of an open clone is a good step! Here are some initial questions I have (and I'm surely missing a lot here due to the unknown-unknowns problem):
- What were your largest concerns when starting an open clone and how did you address them?
- Did you have any design or writing guide posts you followed during the process?
- Is it enough to change all of the language and leave the mechanics intact or does there need to be enough differentiation there, too?