Thanks for asking... I used Apple&#x27;s SpriteKit framework [1][2]. It&#x27;s essentially a 2D graphics rendering framework that primarily acts as an abstraction layer for OpenGL ES. In addition, it also offers several other &quot;nice-to-have&quot; features with regard to 2D game development (e.g., collision detection, particles, physics, etc.)<p>Of course, you could do all of the above without SpriteKit. For example, for all of the rendering, you would simply write everything directly in OpenGL ES.<p>There are also cross-platform options, like Cocos2d-x [3] and Marmalade [4].<p>Finally, if you&#x27;ve read this far, you might be interested in reading my general thoughts and feelings from when I finished the game [5].<p>Cheers!<p>[1] <a href="https:&#x2F;&#x2F;developer.apple.com&#x2F;spritekit" rel="nofollow">https:&#x2F;&#x2F;developer.apple.com&#x2F;spritekit</a><p>[2] <a href="http:&#x2F;&#x2F;www.raywenderlich.com&#x2F;category&#x2F;sprite-kit" rel="nofollow">http:&#x2F;&#x2F;www.raywenderlich.com&#x2F;category&#x2F;sprite-kit</a><p>[3] <a href="http:&#x2F;&#x2F;www.cocos2d-x.org" rel="nofollow">http:&#x2F;&#x2F;www.cocos2d-x.org</a><p>[4] <a href="https:&#x2F;&#x2F;www.madewithmarmalade.com" rel="nofollow">https:&#x2F;&#x2F;www.madewithmarmalade.com</a><p>[5] <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=8888107" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=8888107</a>