MaiZure really called that one!
I'm curious as to what regulars here think about the unlocks though. I really could dig the game a lot more if I had instant access to the content I want. Does it not frustrate others when switching between computers, or when you have to do a reinstall? Does it not make it harder to introduce to your friends?
To begin, player records have been compatible since 0.9.9.0, and KK has said that he will continue to make this work for subsequent versions. Furthermore, the records are also backed up multiple times by default (and they're as easy to move around as copying the player.wad and score.wad files to the other directory). Thus, there shouldn't be detrimental problems with moving to another computer or reinstalling unless the entire DoomRL directory was corrupted or removed. In other words, if you've played a few weeks, you should have everything unlocked, and it can stay with you for as long as you like.
I never keep my records from version to version, but it doesn't matter much anyway since it's quite easy to unlock everything within a few (successful) playthroughs, which shouldn't take more than a few hours. For beginners this isn't as easy to do, but they can keep their records from previous versions if they want everything unlocked as it was before. It's not like there are radical changes to the gameplay with the challenge modes: at most the Angel of Pacifism and 100 could appeal to different types of players, but I highly doubt they'd be any good at them unless they could handle the normal game well enough first. (Other challenges modes, like Angel of Markmanship, Shottgunnery, Impatience, and Purity, can be imitated simply by limiting yourself manually.) The only other unlocks that would be annoying are assembly schematics, but if you're learned a good deal of them before then you can either head over to the Wiki (where they are fully documented) or boot up an old version, write down the recipes somewhere, and use that to make them.
Overall I'm not too concerned about unlocks, but I'm not sure that regular is a good person to ask. If beginners really hate it, I've yet to hear some complaints. (So this would be a place for to say it if they think that!)
And the interface could do with a bit of work too, in my opinion, just to streamline the gameplay a little more. 1)Mouse support is not particularly hard to implement in FreePascal, and I think it could add a tonne to how quick the game plays. Left click move, right click fire, middle click reload - damned fiends can get blasted back to hell without me having to glance at my keyboard! 2)Inventory should perhaps be looked at - stack all ammo together, reduce inven size, and combine the inventory and eq screens so you can compare things easier. Or just add an equipment comparison box in the inventory screen. 3)Change the modified description on items to just "mod" so it doesn't cut off on the right. Lots of other little tweaks can be made to make playing the game that bit more pleasant.
1) Mouse support sounds...awkward. The non-movement makes sense, but moving would either have to be done step-by-step (which is a PAIN for a mouse) or uses auto-run, which could be very disorienting. Note that a lot of movement in DoomRL isn't just going from place to place, as there is plenty of tactical maneuvering involved, and using the mouse for these careful actions may not be ideal (in the same way that trying to play the original with the mouse was extremely awkward for strafing/turning). One thing we could likely attempt to emphasize is the run-mode button, which lets you speed off in a given direction: this can significantly affect the game's pace (in a good way) if used properly. I actually set up my run button for numpad5 (using the numpad for movement) and it allows for a very streamlined usage.
2) The ammo-stack and inventory sizes are actually a part of game strategy, so I'm not too keen to change them for the sake of improving UI. Admittedly it's a little clunky, but you get fairly used to it (in the same way you get used to other game's inventories...at least here the inventory is strictly limited to a single page).
3)This is a definite improvement without real drawbacks, so I see no reason not to do it. (At least, I think people will realize that "mod" stands for "modified" when it shows up that way in-game.)
Really though, any suggestions you have, any at all, should be posted without delay. I agree that there are a lot of really tiny flaws here and there that, when collectively fixed, could remarkably decrease UI distractions from the gameplay. Usually they're either so rare or so small that I forget to post when I think of it and forget, but they are no less important than the other things that are changed over time.