I hope this game gave you lots to learn about mixing UIKit and SpriteKit, texture atlases, scene transitions, and of course destructible terrain – while also giving you another real-world project under your belt. If you’re following this series in order you've now made seven SpriteKit games of varying complexity, so I hope you have all the knowledge you need to get out there and make your own.
If you want to extend this project, you might want to consider starting with the art for a change: I've made it look relatively similar to the original DOS game, but let's face it that will only appeal to fans of retro gaming nowadays! If you're looking to change the code, see if you can make the game track scores across scenes so that players know who is winning.
If you're looking for something harder, make it best of 5: whoever reaches a score of 3 first wins, showing a "you win!" screen of your choosing. And for a real challenge, try to modify the collision detection so that exploding bananas damage all buildings the explosion would have touched rather than just the building the banana touched.
One of the most effective motivators of success is sharing your progress with other people – when you tell folks what you're doing and what you've learned, it encourages you to come back for more, which in turn will help you reach your app development goals faster.
So, now that you've done all the hard work it's time to share your success: tell folks that you've completed this project, either by clicking the button below to start composing a tweet, or by writing your own message from scratch. This will definitely encourage you to keep learning, but it will also help other folks discover my work – thank you!
Paul Hudson is the creator of Hacking with Swift, the most comprehensive series of Swift books in the world. He's also the editor of Swift Developer News, the maintainer of the Swift Knowledge Base, and Mario Kart world champion. OK, so that last part isn't true. If you're curious you can learn more here.