I haven’t published the game yet. The game itself is about 25mb. I tested the game on an iphone 5 and 5s as well as an android kitkat. I also have an Android marshmallow but haven’t tested yet. On kitkat it runs ok. Not perfect but ok. On the iphone it runs much better (very good). Performance depends on how you optimize your code and how advanced you want to go. Some devices will handle performance better than others. Size is not always a main factor. It depends on FPS and how you handle sprites. Duang Sheep (or flappy bird) requires high FPS because it is constant movement. The advantage of flappy bird is very few sprites. FPS can be affected by many factors which aren’t only related by your game but also system usage.