Strange replay settings

Those are advanced settings, as the replay mode is in development/experimental stage, those can be handy for us in certain situations.

The last one (transparency), let you chose if the replay should remember which parts are visible when you recorded the replay (let's say you want to watch the replay later, but use the 'part highlight' feature to only see some parts.

 

Edit: oops, ninja'ed

The "alt" options are leftovers from internal tests that were not fully removed - keep them off to be on the safe side.
As for the transparency setting, here's a brief explanation: https://www.beamng.com/threads/0-12...-thread-read-1-post.53437/page-22#post-861855