The easiest thing to do is to first find out how paranoid you are. If you are as paranoid as me, then you'll likely make a new save when you get a FOF working right. Personally, I have a system. The WIP versions of a WAD are thisorthat(savenumber).wad, and the final is gametype_thisorthat.wad So, I have triadtrials.wad all the way to triadtrials17.wad, along with mta_triadtrials.wad. It's a good habit, especially if you decide three quarters through that the first half of the level is garbage, or the last half for that matter.