He gained a sizeable cult following in the 1990s after releasing several hundred songs of unique and simple music which became an internet phenomenon during the early days of P2P file sharing.
In 1989, Willis began hearing what he called "demon voices" and was diagnosed with schizophrenia. He often mentioned that his demons were named "Heartbreaker," "Nervewrecker," and "Meansucker". He called his psychotic episodes "hell rides". Alternatively, he declared rock and roll to be "the joy ride music" and Willis often indicated that listening to and performing music helped him battle the voices.
In the early 1990s, Willis became creatively active, selling magic marker drawings of the Chicago cityscape on the street. Some of the drawings would later appear on the covers of his albums.
Some of his drawings you can find here.
As a solo artist, Willis created more than 50 albums, each with nearly 30 tracks, full of bizarre, excited, and often obscene rants about crime, fast food, cultural trends, bus routes, violent confrontations with superheroes, commands for his "demons" to engage in bestiality, and praise for his favorite actors, best friends, politicians, and hip-hop and rock artists.
Willis's songs have a very specific form and style which is virtually always followed, leading most listeners to complain that it all sounds the same. Wesley never actually played the notes on his keyboard; he simply used the one-note autochord feature, with preprogrammed rhythms and harmonies. Typically one chord is used for the verses, and a pattern for the choruses and "solo" sections.
If you are still interesting in his music, even after reading this post, then you can download his Greatest Hits album.