Movement: STEP FORWARD, STEP BACKWARD, STRAFE LEFT, STRAFE RIGHT, JUMP
These are your movement actions. If you don't set keys for these actions, you can't move! Congratulations, you're a sitting duck! By default the movement actions are set to the Arrow keys, but those controls suck. Most of you FPS enthusiasts are used to the Halo/CoD controls anyway, so for simplicity's sake, set movement to W-A-S-D. You can go ahead and leave JUMP set to spacebar, as that's what most people are used to anyway.
Don't bother using the LOOK LEFT and LOOK RIGHT actions unless you have a laptop and aim using the keys. With mouselook set to ON (which it should be by default), you can change your angle by moving the mouse around anyway.
You may have noticed FLY/SWIM UP and FLY/SWIM DOWN actions while setting your movement keys. Don't even mess with them, they do absolutely nothing. Now I know what you are probably thinking, "hao doo u move in teh waterz if u cant swim derrrrrrrrrr"
...Okay, maybe you don't think in 1337, but the point is, "Can I still move in water?" The answer is yes, and also no. On most maps, it's safe to enter water and move about, and even if water kills you, it's usually obvious to tell what water is and isn't safe. (Example: Wave Man's non-swim water moves at high speed like an ocean current.)
All weapons still work in water (even the fire ones!), and you can freely move in all directions. The difference between air and water physics? While in water, you jump about two to three times the normal jump height. Don't forget, this is designed like a MegaMan game, kids!
Battling: FIRE, NEXT WEAPON, *PREVIOUS WEAPON, USE ITEM, NEXT ITEM, *PREVIOUS ITEM, *DROP WEAPON, *DROP ITEM
By default, FIRE is set to left-click, and the NEXT/PREVIOUS WEAPON actions are set to the mousewheel. If you have an external mouse, then usually this is perfect for you. ALTERNATE FIRE does nothing in MM8BDM, so don't set any keys to it.
The actions for using support items are a bit hidden from you, though. Just keep scrolling down the controls list and you'll be sure to run into them. As MM8BDM is fairly fast-paced, you want to be able to use an E-Tank or Tango Roll at an instant's notice, so set the USE ITEM key to something easy to press and simple to remember. My friends and I use right-click or the left Shift key.
As there are a lot less items in the game than there are weapons, you don't really need a PREVIOUS WEAPON button as long as you have a NEXT ITEM weapon, and vice versa. Remember to keep the item change buttons nearby and easy to use just like the USE ITEM button.
You may have noticed that near the top of the controls list, in a completely different section than the items section, is a fairly isolated command called USE. In normal Doom games, the USE command opens doors and activates teleporters, but in MM8BDM it does absolutely nothing. Doors, teleporters, wind panels, and the like are activated upon contact, so don't even bother with this. Just remember that there's a clear difference between USE and USE ITEM, okay? If you've actually read this far, congratulations. Type this into the console window for a neat little prize: SKIN AUTO
The last two actions here are DROP WEAPON and DROP ITEM. These are handy for team-based game modes. In a nutshell, you lose the currently equipped weapon/item and throw it slightly in front of you, so a team member can pick it up and use it. I woudn't recommend setting DROP WEAPON, because weapons don't disappear when picked up in MM8BDM under normal server settings.
DROP ITEM is handy though, when your friend desperately needs a W-Tank to refill his Yamato Spear, and you happen to have taken three W-Tanks from the enemy base. Extremely situational, yes, but it's nice to have the option available. Please note that in regular every-master-for-themselves modes like standard Deathmatch and Terminator, the DROP ITEM action does nothing. It's nice to know that you can't accidentally give up your E-Tank to an enemy, eh?
Other Nifty Stuff: SAY, *TEAM SAY, *VOTE YES, *VOTE NO, *CONSOLE OPEN, *SHOW MAP
SAY and TEAM SAY are used for online play. Obviously, SAY allows you to type in text and display it to all users on the server, even spectators. The same is true for TEAM SAY, except that the message is only broadcasted to those players who are on the same team as you. For obvious reasons, using TEAM SAY on a game mode without teams makes the message display only to yourself! SAY is, by default, assigned to T, which is out of the way and easy to reach when you need it. If you would like to use TEAM SAY, I recommend placing it on the Y, 5, or 6 keys. Right next to the SAY button, yet still out of the way so it doesn't get accidentally mashed during a firefight.
The two VOTE actions are used for when someone calls a vote on an online server. Votes do things like propose a possible map change, or kick an abusive user. The default keys are Page Up for YES and Page Down for NO. These are just fine for me, but your mileage may vary, so feel free to stick these anywhere is convenient for you.
An extremely useful yet under-rated action is the SHOW MAP action. Depending on your game settings, it will pull up a gray-and-white map that shows the stage layout as well as your current position, a la Legend of Zelda. Alternatively, it will place a transparent map overlay on your screen, with the map boundaries drawn in a light green color and your player's position represented by your crosshairs. Really easy to use and handy in massive stages like Mr. X's Fortress or Knight Man Castle. If you end up using SHOW MAP, remember to change your game settings to whatever style of map you prefer to use.
The last key that you *might* need is OPEN CONSOLE. Usually, it's out of the way and tucked over in this key --> ` <-- right here. Only advanced Doom/Skulltag/MM8BDM users really need to take advantage of the console. It's mainly used for specialized functions like entering cheats, activating hidden skins, or joining remote servers as an administrator or by IP.
Thanks for reading, and happy fragging!
SmashBroPlusB
You're free to use this and spread the knowledge, but you have to do it for free and you must also give me credit. Failure to credit SmashBro will result in being hunted down and Charge Kick'd in the Crash Bombs, if ya know what I mean. ;)