Anybody who got really excited about programming when they first started learning can probably relate to this. To date, my most god-awful work was a PHP clone of 4chan written in a night and maintained over the course of a few months. If you think you've seen bad code in your life wait until you see a PHP/MySQL website written by a 10th grader in 6 hours.
The beauty of this Terraria clone is that it's a similar type of ordeal, just at such a massive scale that it's truly a work of art.