Movement:

if Input.is_action_just_pressed("left"):
    velocity.x = -1
    $Sprite2D.flip_h = false
elif Input.is_action_just_pressed("right"):
    velocity.x = 1
    $Sprite2D.flip_h = true
if Input.is_action_just_released("left"):
    velocity.x = max(velocity.x,0)
if Input.is_action_just_released("right"):
    velocity.x = min(velocity.x,0)

if Input.is_action_just_pressed("up"):
    velocity.y = -1
elif Input.is_action_just_pressed("down"):
    velocity.y = 1
if Input.is_action_just_released("up"):
    velocity.y = max(velocity.y,0)
if Input.is_action_just_released("down"):
    velocity.y = min(velocity.y,0)

Warp between rooms:

func warp(real_dir,dir): # ULDR
    var odd = dir % 2 == 1
    
    var vpos = position
    var off = -2*MARGIN
    var offw = SIZE - 2*MARGIN
    
    var diff = player.position - (position + Vector2(SIZE/2,SIZE/2))
    player.position = diff.rotated((real_dir - dir) * PI/2) + position + Vector2(SIZE/2,SIZE/2)
    
    if dir >= 2:
        off = SIZE + 2*MARGIN
        offw = 2*MARGIN
    
    if odd:
        vpos = Vector2(vpos.y,vpos.x)
        player.position = Vector2(player.position.y,player.position.x)
    
    if warps[dir] == "":
        player.position.y = vpos.y + off
    else:
        var level_pos = locate_level(warps[dir])
        if odd:
            level_pos = Vector2(level_pos.y,level_pos.x)
        player.position.x += level_pos.x - vpos.x
        player.position.y = level_pos.y + offw
    
    if odd:
        player.position = Vector2(player.position.y,player.position.x)
    
    player.velocity = player.velocity.rotated((real_dir - dir) * PI/2)
    
    player_inside = not warps[dir] == name