gistfile1.js

cursores = game.input.keyboard.createCursorKeys();

if(cursores.left.isDown) {
    ...
} else if (cursores.right.isDown) {
    ...
} else if (cursores.up.isDown) {
    uno.body.velocity.y = -1;
    uno.animations.play('front')
    lastDirection = 'front';
} else if (cursores.down.isDown) {
    uno.body.velocity.y = 1;
    uno.animations.play('back');
    lastDirection = 'back';
} else {
    uno.body.velocity.x = 0;
    uno.body.velocity.y = 0;
    uno.animations.play('stand_' + lastDirection);
}