After the main character's creation, the team went into three months of developing the game. The game first became functional in April 1995 and became playable in June 1995. The first 3 levels in the game were completed by August 1995. However, they were judged to be too difficult to appear so early in the game and were moved to the game's power plant area. Artist Charlotte Francis joined Naughty Dog at around this time. In September 1995, a videotape of "Crash Bandicoot" was shown to Sony Computer Entertainment behind closed doors. While playing the game during development, Rubin realized that there were many empty areas in the game due to the PlayStation's inability to process numerous on-screen enemy characters at the same time. Additionally, players were solving the game's puzzles too fast. Rubin soon came up with the idea of a box and putting various symbols on the sides to create puzzles. Breaking these boxes would serve to fill in the boring parts of the levels and give the player additional puzzles. The first "crate" was placed in the game in January 1996, and would become the primary gameplay element of the series. Willy the Wombat's destruction of the crates would eventually lead him to be renamed "Crash Bandicoot". In March 1996, Sony agreed to publish "Crash Bandicoot", which went into the alpha stage in April 1996. "Crash Bandicoot" was first shown at the Electronic Entertainment Expo in May 1996.