Beaten UP Moviment style help

hello, guys i was thinking in trying to make a prototype game for a beat en up game using 3d characters however i want it in 2.5d style, then the issue is the “moviment, i want which my character and enemies can only “look” or turn” to right or left" never "up or “down” like in old arcade games or at last when “attacking” they only attack looking at left and right even if they are looking at up or down, in case i want then being able to look to up or down.

well bu to make things simple i just want then to aways be looking left or right, like if i press “up” to make then move “up” they walk to up based on if they are looking at left of right like, if the character is looking at “left” then when i press "up it will move up but keep looking at “left”, if i move down then same, if i make it look to “right” then when moving to up or down it will “walk” as if looking at right.

the same for battle they aways will be "punching at “left or right” never up or down. well any attack will follow this rule.

i would love any help towards it.