New Content
This post will cover all suggestions for new content to add to the game. It is organized by general features, equipment/items, enemies, new challenges, and miscellaneous stuff (a traits and special levels section could be added too if Kornel says they're on the table and anyone has decent suggestions for them).
Features
[ ] Have the trait selection screen be more color-coded (example by Mader Levap): 1 (https://tinyurl.com/5n7chwca) 2 (https://tinyurl.com/2p8n7kxa) (https://i.imgur.com/gUyYpVB.png)
[ ] Add a toggle in the settings that turns off the powerup overlay filters of Berserk, Invulnerability, and Envirosuit. 1 (https://tinyurl.com/bdfh5ru6) 2 (https://tinyurl.com/yc3243nb)
[ ] When playing Nightmare or Angel of Darkness, have a message that informs you when every unique enemy on the floor has been killed at least once, so that a player going for 100% kills but not meticulously disposing of every corpse doesn't need to keep bringing up the player info screen to check when they have gotten 100% kills on any floor. Also maybe consider adding a visual indicator to respawned enemies to help immediately discern them, such as some dull-colored aura? 1 (https://discord.com/channels/372448815195619330/1307032080596865126/1312257575789662250)
[ ] Have the player info screen display the amount of ingame time the player has spent on the current floor, to make it easier to track the Enraged Timer and other time-based events. 1 (https://forum.chaosforge.org/index.php/topic,8853.msg71184.html#msg71184)
[ ] Add trap rooms. These would have a powerup/exotic/unique item inside, and when picked up, has a randomized chance of spawning enemies similar to a summon enemies lever, or floods the room with acid, lava, or blood. The weight of the powerups/exotics/uniques would not impact the rest of the floor, and any enemies spawned by the trap will not give EXP. The chance of the trap activating can be affected by depth level and/or difficulty. 1 (https://tinyurl.com/mrxsur9b) 2 (https://tinyurl.com/y6e59p42) 3 (https://tinyurl.com/n2u3erd4) 4 (https://tinyurl.com/5mefmdy2) 5 (https://tinyurl.com/42vsnavh)
[ ] Add a replay system to record and playback runs. 1 (https://forum.chaosforge.org/index.php/topic,8853.msg71529.html#msg71529) 2 (https://forum.chaosforge.org/index.php?topic=8853.msg71531#msg71531)
[ ] Consider adding an option to change your name ingame? 1 (https://forum.chaosforge.org/index.php/topic,8853.msg71532.html#msg71532)
Equipment, assemblies, and other Items
[ ] New exotic: Acid-Proof Armor, which is 3 Protection, 95% Acid Resistance, -10% movement speed, everything else normal. (Could alternatively be named "Baron's Hide" to have a more flavorful name) 1 (https://tinyurl.com/4huckfe3) 2 (https://tinyurl.com/cdzv69j9)
[ ] New exotic: Glass Armor, which is 0 Protection, 50% Durability, 50% all resistances. 1 (https://tinyurl.com/4huckfe3) 2 (https://tinyurl.com/cdzv69j9)
[ ] New exotic: Glass Shield, which is 0 Protection, 50% Durability, 80% all resistances, cannot be repaired, cannot be modded, doesn't degrade. 1 (https://tinyurl.com/4huckfe3) 2 (https://tinyurl.com/cdzv69j9) 3 (https://tinyurl.com/mt7us4vd) 4 (https://tinyurl.com/y2k79nst)
[ ] New unique: Dimensional Boots, which is 4 Protection, -30% Move Speed, +30% Knockback, and when worn, you move two tiles for each movement rather than the usual one tile. (However you can allow the player to move only 1 tile by holding Shift as they move, so that they don't need to switch boots for finer movement control.) 1 (https://forum.chaosforge.org/index.php/topic,8853.msg71053.html#msg71053)
[ ] New unique: M6D Magnum (from Halo: Combat Evolved), 3d6 pistol with a 12 round clip and standard firing time, which has the perk of having a special aimed shot alt-fire that has autohit (but still has the doubled firing time penalty). Also make it moddable by Technicians. 1 (https://forum.chaosforge.org/index.php/topic,9268.msg71595.html#msg71595)
[ ] New unique: Big Fucking Shotgun, which is a shotgun with 40d5 plasma damage and a new "BFS" shotgun blast type with a max range of 10, spread of 5, and dropoff reduction of 10% per tile. However it has a clip size of 40 and requires 40 cells to shoot, has a 2 seconds firing time, and a 4 seconds reload time. (In effect, this weapon is a more faithful mechanical recreation of Doom's actual BFG). Also make it moddable by Technicians.
[ ] New unique: Unmaker (Quite complicated, see linked post for details on how it should function) 1 (https://forum.chaosforge.org/index.php/topic,9268.msg71608.html#msg71608)
[ ] New assembly: Scouting Armor (any armor + AS), which is original with +1 Vision, +10% speed. 1 (https://tinyurl.com/3e3whj5r)
[ ] New assembly: Blastproof Armor (any armor + TF), which is original with half damage to explosions, +30% knockback. 1 (https://tinyurl.com/3e3whj5r)
[ ] New assembly: Sniper Rifle (Chaingun + BAS), which is original with auto-hit property. (Also a reference to Doom's actual Chaingun being a perfectly accurate sniping weapon when two-tapping it). 1 (https://tinyurl.com/4huckfe3) 2 (https://tinyurl.com/cdzv69j9)
[ ] New assembly: Laser Blade (Combat Knife + BTN), which is 5d5 plasma damage with 0.8 sec firing speed, -2 accuracy, and when equipped, it has the ability to reduce any plasma hit that deals less than 5 damage before armor/resistances to 0 (or if that is too difficult/annoying to program, alternatively just have it give +50% plasma resistance when equipped). Also make it indestructible, so its throwing altfire can be utilized without risking losing it. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71018#msg71018)
[ ] New set: Tactical Set (Tactical Armor + Tactical Boots), which gives Dodgemaster. 1 (https://tinyurl.com/bdfh5ru6) 2 (https://tinyurl.com/2p9fdukf)
[ ] New set: Bruiser Set (Acid-Proof Armor/Baron's Hide + Acid-Proof Boots), which gives 100% acid resistance. 1 (https://forum.chaosforge.org/index.php/topic,8853.msg71035.html#msg71035)
Enemies
Currently no new ideas
New challenge ideas
[ ] "Angel of Gladiating" and "Angel of Labyrinth" (or any other appropriate name): The former challenge will have all floors be Arena-type levels, and the latter challenge will have all floors be mazes. Alternatively, the challenges can be combined together and caves could be thrown into the mix for a "hard level types only" challenge. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Angel of Misfortune" (or any other appropriate name): Every floor will have a level event. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Angel of Spilling" (or any other appropriate name): Your inventory will be reset to the starting loadout upon entering every floor, emulating the popular Pistol Start challenge in Doom. The starting loadout may be modified to give you more of the standard weapons and some ammo for them, so that you're not practically forced to use Pistol builds. Exotics/uniques may also have increased chances of spawning to compensate for the temporary equipment, and an exception to resetting inventory could be made when entering boss and special levels, so that they all remain beatable. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Angel of Turbo" (rudimentary placeholder name, can be replaced with something better): All enemies are 20% faster, recreating Doom's own "fast monsters" setting that DRL currently lacks an equivalent to. An Archangel version can also be made that makes enemies even faster.
[ ] "Angel of Drought" (alternatively "Angel of McGee" if you want to get clever with the reference, named after the Doom developer that made some of Doom's most infamous resource deprivation maps): All ammo drops will contain only a third of the usual ammo (including ammo boxes, but dropped weapons will still contain their full ammo), and melee weapons will be unusable so the player cannot easily bypass this challenge with melee, while Brute will also give no melee damage boost so the player's fist remains worthless against anything bigger than Formers and Imps. 1 (https://discord.com/channels/372448815195619330/1372975499151933450/1412118579700175009)
[ ] "Angel of Pestilence": The player's health steadily drains nonstop, as if it were a permanent deadly air event that doesn't affect enemies. You can additional make an Archangel version, where the health drain is much faster. 1 (https://discord.com/channels/372448815195619330/381122638736523265/1416821673998549012)
[ ] "Archangel of Darkness": You have a vision radius of 4 and enemies revive, but you gain x2.5 experience. 1 (https://tinyurl.com/5n7chwca) 2 (https://tinyurl.com/2p8n7kxa) 3 (https://tinyurl.com/2p9fdukf) 4 (https://tinyurl.com/2p82nuyu) 5 (https://tinyurl.com/bdeuhtmf)
New level events
[ ] "Mortuary event": All enemies will immediately die when entering the floor (and not give any EXP in the process), then a random number of Arch-Viles will be spawned around the floor (and especially bad level rolls on UV/N! could spawn Nightmare Arch-Viles). Also disable the "reveal enemies" mechanic and stair sense in this event. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Max Carnage event": Emulates Angel of Max Carnage for a single level, i.e. the player and enemies always deal maximum damage while having +12 accuracy. Particularly bad level rolls should instead have a "Snake Eyes" event, where only enemies always deal maximum damage and have +12 accuracy. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Masochism event": Emulates Angel of Masochism for a single level, i.e. the player will be unable to heal through conventional means until they exit the floor. To prevent a player from getting screwed by entering such a floor at low health, have the player get supercharged upon entering the floor. 1 (https://forum.chaosforge.org/index.php?topic=8812.msg71015#msg71015)
[ ] "Malice event": The Enraged Timer gets reduced to 2 and a half minutes for the floor, this event should only occur lategame in HMP+. 1 (https://discord.com/channels/372448815195619330/381122638736523265/1417156560681177243)
[ ] "Blood floods": Lategame floods on UV/N! can flood with blood.
[ ] "Reinforcements event": At regular time intervals (which are lower the higher the difficulty), a random enemy based on current depth will spawn in on a random spot on the map, which will continue until the player kills all enemies on the floor or 12 ingame minutes pass. These "reinforcements" will not give any EXP, but will drop any inventory they have, like enemies spawned by a summon lever will.
[ ] "Turbo event": All enemies on the floor get a +10% speed bonus. If on UV/N!, especially bad level rolls can result in a harder version of this event where enemies get a +20% speed bonus.
Miscellaneous
[ ] New powerup: Partial Invisibility globe, which when active can either make enemies shoot at random angles instead of directly at the player (most faithful to how Doom's actual Partial Invisibility works but also most chaotic and may have conflicts with how VMR's targeting works), reduce enemy accuracy and increase the player's dodging rate like Running does (most banal but functionally useful option), work like JHC's stealth does where enemies won't see the player until the player attacks or it wears off (which also replicates how the powerup works in ZDoom-based source ports), or some combination of these effects. 1 (https://discord.com/channels/372448815195619330/381122638736523265/1417964379957362708)