Local play with two people on a single keyboard across 20 different key bindings is actually a completely ridiculous impractical idea that has never worked in any game. The reason for that is that most keyboards let you hold 4-6 keys at max, so two players playing on the same keyboard are going to be ghosting each other and killing each other's inputs. You can connect absolutely anything else to the computer though (like a pad from your console, or a cheap knockoff one for a few bucks) and have one person play on the keyboard with hands nicely spread out and the other on the controller.
Melty is sometimes considered a keyboard game exactly because PC-only people with no idea about fighting games tend to wander to it from other TM media and then find out it's actually pretty tight. The basic button layout is trash though, people usually play on WASD and either directional buttons or numpad. Now, this sort of game is meant for an arcade stick or a pad where directions are on the left, but a keyboards's directions are on the right. Default melty key bindings are also this way iirc. Some people change it to play with their hands flipped for easier movement, some don't and just put the buttons on directionals/numpad.
If you're playing community version versus, you can bind your keys through ccaster. If you're playing steam version arcade, you can also bind your keys in settings. If you're playing community version/Carnival Phantasm disc arcade, you're screwed and have to use the default, but then CPU doesn't require to be an amazing player and people have played that way for a while. You could also use some keybinding software like joy2key I guess.
- - - Updated - - -
The games have begun, first in Brazil.