Code:

//Configure app for landscape game mode.

cfg.Game, cfg.Landscape

//Handle game loading.
function OnLoad()
{
    //Enable physics and enclose scene with walls.
    //Note: we set zero gravity her cos we are in space!
    gfx.AddPhysics( 0 )
    gfx.Enclose( -1, "left,top,right,bottom", 0.1,0.1,0.1, 0.05 )
    
    //Create background.
    space = gfx.CreateBackground( "Img/nebulus_1.png" )
    
    //Create sprites.
    ship = gfx.CreateSprite( "Img/ship_1_red_3128x179x17", "ships" )
    missile = gfx.CreateSprite( "Img/missle_1_flame_792x132x18", "missiles" )
    rock = gfx.CreateSprite( "Img/meteor_2_816x1971x3x9", "rocks" )
    explode4 = gfx.CreateSprite( "Img/explosion_4.json" )
    explode8 = gfx.CreateSprite( "Img/explosion_8.json" )
    gameover = gfx.CreateSprite( "Img/game_over.png" )
    
    //Create sounds.
    soundExp1 = gfx.CreateSound( "Snd/explosion_1.mp3" )
    soundExp2 = gfx.CreateSound( "Snd/explosion_2.mp3" )
    soundFire = gfx.CreateSound( "Snd/missile_1.mp3" )
}

​

//Called when game has loaded.
function OnReady()
{
    //Set background.
    gfx.AddBackground( space )
    
    //Add game objects to screen.
    AddShip()
    AddExplosion()
    AddButtons()

    //Add rocks every so often
    setInterval( AddRock, 2000 + 2000*Math.random() )
    
    //Start game
    gfx.Play()
}

​

//Update game objects.
function OnAnimate( time, timeDiff ) 
{    
    //console.log( gfx.keyDown )
    
    //Make background drift slowly
    space.Scroll( 0, 0.001 )
    
    //Make rock explosions drift and fade
    if( explode8.x > 0 ) { 
        explode8.y += 0.001
        explode8.alpha -= 0.004
    }
    
    //Limit range of missiles
    if( missile.x < -0.01 || missile.x > 1.01 || missile.y < 0.01 || missile.y > 1.01 )
        gfx.RemoveSprite( missile )
}

​

//Add a new ship to screen.
function AddShip()
{
    //Add ship image to center of screen and show frame 8.
    gfx.AddSprite( ship, 0.45, 0.5, 0.1 )
    ship.Goto( 8 )
    
    //Set physics properties for ship.
    //group, type, density, bounce, friction, linearDamp, angularDamp
    ship.SetPhysics( -2, "dynamic", 0.9, 0.9, 0.3, 0.3, 0.3 ) 
    ship.SetShape( "rect", 0.7, 0.7 )    
    //ship.SetVelocity( 0.02, 0, 0.3 )
}

//Add rock image to screen, with physics and animation.
function AddRock()
{
    //Add a new rock image to screen at random x location.
    rock = gfx.CreateSprite( "Img/meteor_2_816x1971x3x9", "rocks" )
    var size = 0.1+0.1*Math.random()
    gfx.AddSprite( rock, Math.random()*0.7, -0.3, size )
    
    //Set physics properties for rock.
    rock.SetPhysics( -1, "dynamic", 0.9, 0.9, 0.9 )
    rock.SetShape( "round", 0.5 )    
    rock.SetVelocity( -0.1+0.2*Math.random(), 0.02/size, -0.05+0.1*Math.random()/size )
    rock.Play( 0, 0.3 )
}

​

//Add explosion sprites off-screen (prevents slight delay on first use)
function AddExplosion()
{
    gfx.AddSprite( explode4, -1,0, 0.7 )
    gfx.AddSprite( explode8, -1,0, 0.5 )
}

​

//Add control buttons for mobile.
function AddButtons()
{
    //Left stick
    var stickSize = 0.08, stickLeft = 0.02
    leftStick = gfx.CreateCircle( stickSize, 0xeeeeee )
    gfx.AddGraphic( leftStick, stickLeft, 1-leftStick.height*2 )
    leftStick.alpha = 0.1
    
    //Right stick
    rightStick = gfx.CreateCircle( stickSize, 0xeeeeee )
    gfx.AddGraphic( rightStick, stickLeft + leftStick.width*1.5, 1-rightStick.height*2 )
    rightStick.alpha = 0.1
    
    //Forward stick
    fwdStick = gfx.CreateCircle( stickSize, 0xeeeeee )
    gfx.AddGraphic( fwdStick, stickLeft + leftStick.width*0.75, 1-fwdStick.height*3+0.02 )
    fwdStick.alpha = 0.1
    
    //Reverse stick
    revStick = gfx.CreateCircle( stickSize, 0xeeeeee )
    gfx.AddGraphic( revStick, stickLeft + leftStick.width*0.75, 1-revStick.height-0.02 )
    revStick.alpha = 0.1
    
    //Fire button
    fireBtn = gfx.CreateCircle( stickSize*1.25, 0xeeeeee )
    gfx.AddGraphic( fireBtn, 1-fireBtn.width-0.02, 1-fireBtn.height*1.5 )
    fireBtn.alpha = 0.1
}

​

//Handle key presses and screen touches.
function OnControl( touchState, touchX, touchY, keyState, key )
{
    //Check for arrow keys or joystick touches
    if( key=="ArrowLeft" || leftStick.Contains(touchX,touchY) && touchState=="Down" ) 
    { 
        ship.AddVelocity( 0, 0, -0.2 )
        ship.PlayRange(8,10,0.5)
    }        
    else if( key=="ArrowRight" || rightStick.Contains(touchX,touchY) && touchState=="Down" ) 
    { 
        ship.AddVelocity( 0, 0, 0.2 )
        ship.PlayRange(6,8,-0.5) 
    }
    else if( key=="ArrowUp" || fwdStick.Contains(touchX,touchY) && touchState=="Down" ) 
        ship.AddVelocity( 0, -0.1, 0, true )    
        
    else if( key=="ArrowDown" || revStick.Contains(touchX,touchY) && touchState=="Down" ) 
        ship.AddVelocity( 0, 0.1, 0, true )    
    
    //Check for fire key (space bar)
    else if( key==" " || fireBtn.Contains(touchX,touchY) ) 
        FireMissile()
    
    //Else straighten up ship
    else ship.PlayTo( 8 )
}

​

//Fire a missile from ship
function FireMissile()
{
    //Check if a missile is already in flight.
    if( missile.GetVelocity() > 0 ) return
    
    //Show missile.
    var x = ship.x + ship.width/2 - missile.width/2
    var y = ship.y + ship.height/2 - missile.height/2
    gfx.AddSprite( missile, x, y, 0.02, 0.07, ship.angle )
    
    //Set missile physics (Note: we use negative group 
    //nums to prevent interaction between ship and missile).
    missile.SetPhysics( -2, "dynamic", 0.001 ) 
    
    //Start missile animation and set its speed.
    missile.Play( 0, 0.1, true )
    missile.SetVelocity( 0,-0.4, 0, true )
    
    //Play firing sound.
    soundFire.Play()
}

​

//Handle sprite collisions.
function OnCollide( a, b )
{
    //console.log( "a:" + a.x + " b:"+b.x )
    
    //Handle missile and rock collision.
    //Note: collision groups are sorted alphabetically.
    if( a.group=="missiles" && b.group=="rocks" ) 
    {
        //Remove missile and rock.
        gfx.RemoveSprite( a )
        gfx.RemoveSprite( b )
        
        //Show rock explosion.
        var x = b.x + b.width/2 - explode8.width/2
        var y = b.y + b.height/2 - explode8.height/2
        gfx.AddSprite( explode8, x, y )
        explode8.alpha = 1
        explode8.Play( 0, 1, false )
        soundExp1.Play()
        
        //Add another rock after 2 seconds.
        setTimeout( AddRock, 2000 )
    }
    //Handle ship and rock collision
    else if( a.group=="rocks" && b.group=="ships" )
    {
        //Remove ship
        gfx.RemoveSprite( b )
        
        //Show ship explosion.
        var x = a.x + a.width/2 - explode4.width/2
        var y = a.y + a.height/2 - explode4.height/2
        gfx.AddSprite( explode4, x, y )
        explode4.Play( 0, 1, false )
        soundExp2.Play()
        
        //Vibrate device
        gfx.Vibrate( "0,100,30,100,50,300" );
        
        //Finish game (after 1 second delay)
        setTimeout( GameOver, 1000 )
    }
}

​

//Show game over text and stop game.
function GameOver()
{
    //Add game over sprite
    gfx.AddSprite( gameover, 0.3, 0.45, 0.4, 0.1 )
    
    //Cause sprite to fade in and then throb
    gameover.alpha = 0
    var throb = function() { gameover.Tween( {alpha:0.5}, 600, null, 99, true ) }
    gameover.SetTween( {alpha:1}, 1000, null, 0, false, throb )
    gameover.PlayTween()
}