Quote from Bismuth:
As for individual levels, I believe the best would be to have saves that are done exactly after the level cutscene, like I did in my DM and RoS segmented runs. The rules would be that it is forbidden to have weapons from "later" levels, basically to have anything that you shouldn't have at this point in the game (for example torpedo launcher in River of Souls). Basically, what I did for my saves was that I did a run of PoA, I saved after entering DM, I did a segmented run of DM, I saved after entering RoS, then I did a segmented run of RoS.
It would also be possible to warp to the individual levels right from the start of the game – in other words, you start each level with only the talon, bow, flare gun and three lives. This does not seem to be a huge problem, as new weapons are found along the way and usually not so much time is wasted by killing enemies. Drawbacks would be that it requires cheating (the level warp cheat) in the first place and it's certainly not the fastest it can be (imagine destroying the force fields in the Hive with a plasma rifle).
The logic of the new level order sounds right, some testing would be nice. I like the unorthodoxy of it. :-) I think it would be interesting to see how much of a benefit a firestorm cannon or missile launcher would be in River of Souls.