         leftPointLbl.text = String(GameState.shared.leftScore)
         rightPointLbl.text = String(GameState.shared.rightScore)
         
-        self.physicsWorld.gravity = CGVector.init(dx: 0.0, dy: 0)
+        self.physicsWorld.gravity = CGVector.init(dx: 0.0, dy: -6)
         physicsWorld.contactDelegate = self
         
         NotificationCenter.default.addObserver(self, selector: #selector(bombAttack(notification:)), name: NSNotification.Name("bomb"), object: nil)

    
    func didBegin(_ contact: SKPhysicsContact) {
        
        if (contact.bodyA.node == leftSquirrel && contact.bodyB.categoryBitMask == PhysicsCategory.LeftBomb) ||
            (contact.bodyA.node == rightSquirrel && contact.bodyB.categoryBitMask == PhysicsCategory.RightBomb) ||
            (contact.bodyB.node == rightSquirrel && contact.bodyA.categoryBitMask == PhysicsCategory.RightBomb) ||
            (contact.bodyB.node == rightSquirrel && contact.bodyA.categoryBitMask == PhysicsCategory.RightBomb) {
            return
        }
        
        if let bodyOne = contact.bodyA.node as? SKSpriteNode, let bodyTwo = contact.bodyB.node as? SKSpriteNode {
            bombExplode(bodyOne: bodyOne, bodyTwo: bodyTwo)

        
        bomb.physicsBody = SKPhysicsBody(rectangleOf: bomb.size)
        bomb.physicsBody?.categoryBitMask = bombCategory
        //bomb.physicsBody?.contactTestBitMask = PhysicsCategory.All
        bomb.physicsBody?.collisionBitMask = physicsCategory
        bomb.physicsBody?.affectedByGravity = false

        
        addChild(bomb)
