An example of simple platform character movement in Godot Engine

BasicMovement.gd

extends KinematicBody2D

const FLOOR_NORMAL = Vector2.UP

export(float) var speed = 500.0
export(float) var gravity = 2000.0

var direction = Vector2.ZERO
var velocity = Vector2.ZERO

onready var sprite = $Sprite

func _physics_process(delta):
	velocity.y += gravity * delta
	velocity = move_and_slide(velocity, FLOOR_NORMAL)


func _unhandled_input(event):
	if event.is_action("left") or event.is_action("right"):
		update_direction()


func update_direction():
	direction.x = Input.get_action_strength("right") - Input.get_action_strength("left")
	velocity.x = direction.x * speed
	if not velocity.x == 0:
		sprite.flip_h = velocity.x < 0

SlopeMovement.gd

extends KinematicBody2D

const FLOOR_NORMAL = Vector2.UP
const SNAP_DIRECTION = Vector2.DOWN
const SNAP_LENGTH = 32

export(float) var speed = 500.0
export(float) var gravity = 2000.0

var direction = Vector2.ZERO
var velocity = Vector2.ZERO
var snap_vector = SNAP_DIRECTION * SNAP_LENGTH

onready var sprite = $Sprite


func _physics_process(delta):
	velocity.y += gravity * delta
	velocity.y = move_and_slide_with_snap(velocity, snap_vector, FLOOR_NORMAL, true).y


func _unhandled_input(event):
	if event.is_action("left") or event.is_action("right"):
		update_direction()


func update_direction():
	direction.x = Input.get_action_strength("right") - Input.get_action_strength("left")
	velocity.x = direction.x * speed
	if not velocity.x == 0:
		sprite.flip_h = velocity.x < 0