Good to know about the A key, thanks for that! I assume that's a fairly new feature?
I should have known better than to write 'every' player, because that is guaranteed to get all the 'oh but I didn't' players to jump on the thread. I would be very very surprised if the vast majority of DoomRL players hadn't checked the assembly wiki page at least. It's currently the only page that I consider required viewing, the rest depends on how spoiled you like things.
I think I'm actually quite careful about not spoiling my own game too much, I do like discovery and I love the Roguelike idea of the player getting better being much more important than your character getting better - it is, after all, a key element of what distinguishes roguelikes from grindy RPGs and MMOs. That's why I think that in this age of the internet and wikis the balance between given information and hidden information has to be very carefully considered. I really really want to be able to play any given roguelike without EVER consulting a wiki for anything. So far the only really fleshed out roguelikes that have got the balance right for me are DCSS and Brogue... Brogue being the perfect example and DCSS barely scraping a pass. DoomRL is just too far out on a limb with all its deliberately hidden information and really hard to grasp mechanics. It really worked with it's simple coffee-break origins when all you were trying to do was kill the cyberdemon, but now it just makes things confusing for new players and diamond badge hunters alike.
I do agree that GUI clutter should be avoided. I agree that spoiling the limited selection of monsters would be pointless - you can get a feel for how to handle them very quickly. There is a lot of unused space in menu screens that could be put to better use without them feeling 'cluttered' though.
I also agree that the game is forgiving enough to let you win without any spoilers, but I disagree with the implications of "If you want to handle the tough stuff then yes, you'll certainly want to take whatever advantage you can get, but by then you're already playing a very different game." You should be able to attempt diamond badges using only the information provided in-game, and I don't believe that is currently really feasible for most people.
I've played hundreds and hundreds of games, and I still don't really understand shotguns, despite them being my favourite weapon. That's wrong. I think I die more often with a plasma shotgun than a shrapnel one because I never know if I'm going to destroy walls or not, and sometimes when I'm sure I've got all those lost souls covered I haven't, I die and that sucks. I've got all the basic assemblies and two advanced assemblies, but having looked at the wiki I can see there's no way I'd ever be able to guess all the remaining ones, especially with all the purple mods required. That's wrong. I've shot perhaps hundreds of thousands of bullets and yet I still have only the faintest hunch of a feeling as to how my point-blank hit % relates to hitting a monster at the edge of my vision. I think sniper packs are good...? They must be, right? Anyway, I think I've over-stated my case a little too vehemently and I doubt it'll make much difference so I'll let it drop, but I really hope the designers at least think a little on these points, as I'd love to see DoomRL become as polished as Brogue one day.