By the way, if a mod is here: I think I accidentally downvoted the above comment. (More precisely, my cat and Vimium did.) I tried to reverse it but I doubt it worked. Please remove the downvote if it's still there.
This is so true. I developed a space shooter for iOS, and it was quite a challenge. This was my first game, and what I found to be quite interesting is just how much is involved in simply finishing a game. For example, every little detail that it takes to make something commercial-quality, like graphics [1], compelling music, game-play, rock-solid frame-rate, user interface, all of the timers that need to be managed, transitions between levels, and in my case, some interesting mathematics (I implemented a Catmull-Rom algorithm to generate flight paths for the enemy drones on one level)... the list goes on.
[1] Incidentally, the article quoted Daniel Cook. For my game, I used Tyrian graphics that he created. He made them available under a Creative Commons license.