A brief comment on these rules, based on actual thought of a possible play....
The problem with these kinds of rules is that it just allows the GM to abuse the players.
For example, I was playing a d20 Modern TrueTales Conan game, and my character (this was over in Hawaii. The game was set there, but we weren't actually playing there. We were playing over at the usual house in New Jersey. A couple of us have been to Hawaii in real life, and I know a couple of people that grew up there, but I don't think that's really important to the discussion) was trying to break into some guy's house so he could assassinate someone (it was a Stygian sorcerer that was hiding out, and sold polished bottle caps on Waikiki as a cover for his drug smuggling operation.
Anyway, there was this kind of shallow pit, that had lava in it. Now, this lava was old... like... I dunno, years or something. Anyway, the pit was maybe a foot or two down below the surface, and the GM had me make a climbing check to make climb down the two feet. It was kind of challenging (DC 37) and before I rolled, I had my cat lick my dice for luck. It's always worked before. Anyway, the GM said that was interfering with the dice, so I could either use Bob's unlucky dice (he always takes them to the bathroom with him) or the DC would have to be raised to counterbalance the cat lick luck.
I figured I'd take my chances with the higher DC, and rolled a 2. I almost made it, but not good enough. So I dropped the two feet down, and the GM said my character was dead. I asked why, and he started waving around this book.
I argued that it didn't apply to old lava, only new lava but he said that since the rules only said "lava" the age didn't matter, and I could just suck it up. I tried pointing out that the example given was explicitly for D&D, but we were playing d20 Modern TrueTales Conan
I'm really not happy with this product, and have given it a -4 rating. I'm going to post a review, and let everyone know how broken this makes the game, and how this is just an ENWorld darling. I heard from an EXTREMELY RELIABLE RESOURCE that these rules were going to be used for 4th Ed, and were just being put out like this as a sort of playtest, even though they're already in the rules. Since I know this is true (Sry can't reveal the name of my source, but he's intimately involved with the entire design process and talks to some of the designers almost every day, and games with them too) I hope they rewrite the rules, so that way 4th Ed isn't completely broken. Otherwise Lava will be the "must have" weapon, and you won't be able to go out adventuring if you don't have some along.
To Reiterate, the rules are completely broken!!! It doesn't even talk about how this would work with Damage as DR!!! I was talking with my good friend (he was friends with the guy that taught Gygax how to play D&D, and has played D&D for over 40 years himself.) and he totally agrees with me that this is just a lame way to be able to TPK people. He said he expects to see Lava builds over on the WotC optimization boards any time now.