I spent countless hours taking new versions of the game Jon had been working on, breaking them in every possible way, and then documenting how the glitches could be achieved and informing Jon so he could fix them. From 2009-2012, the process was typically the two of us in a computer lab at a local college finding glitches. From 2012-2015, typically Jon would send me a copy, and I would find and document glitches in a Google Doc several pages long.
Jon and I made the sound effects together - here are some of the sounds I made. The sound effects were mostly made in 2016. Some of the walking and running sounds were recorded together (sadly I don't have any of them).
Jon and I composed the music together using Reason software. The ambient music in each area was non-rhythmic, and all composed in the same key to make seamless crossfading possible. Jon put it all together into a soundtrack on Bandcamp.
Each piece of music was broken into separate tracks and exported separately, so they could be individually controlled as separate musical layers in the game that could be faded up and down based on the location of the player. Here's the layers of the underwater world as an example.