There is actually quite a bit known about this game. The plot was that the Evil Twins and the Ants were taking over the world and Crash had to travel to different planets in different dimensions using the Psychetron. Most of the enemies set to appear can be seen in the Twinsanity concept art (the goat guy, rock bees, etc). There were worlds set to appear: a fish-people inhabited world, a planet known as Gaudi, and a place called the "Hanging City", where the rich people live in the hanging part and the poor live in the slums below.
The fish people can be seen in the Twinsanity concept art, along with a worker from the Hanging City Slums (the turtle guy with the backpack). A designer of the game released this information. There is also a concept for the game showing Crash in a space suit but no more information has been found about it. Further concept art reveals that many past characters such as Komodo Joe, Ripper Roo and Koala Kong were set to return. Crash was also going to have to undertake quests to gain the trust of the inhabitants of each world.
The storyline of the game was changed to what became Twinsanity because the original plot was too similar to the game Ratchet and Clank, in the sense that the antagonists were taking the best parts of other planets to make their own. (It's likely N. Sanity Island was one of the best spots on Earth, as it concerned Crash.)
|Crash Bandicoot Series Games|
|Main games||Crash Bandicoot (1996) • Crash Bandicoot 2: Cortex Strikes Back (1997) • Crash Bandicoot 3: Warped (1998) • Crash Bandicoot: The Wrath of Cortex (2001) • Crash Twinsanity (2004) • Crash of the Titans (2007) • Crash: Mind Over Mutant (2008)|
|Crash Bandicoot racing series||Crash Team Racing (1999) • Crash Nitro Kart (2003) • Crash Tag Team Racing (2005) Crash Bandicoot Nitro Kart 3D (2008) • Crash Bandicoot Nitro Kart 2 (2010)|
|Crash Bandicoot party series||Crash Bash (2000) • Crash Boom Bang! (2006)|
|Handheld series||Crash Bandicoot: The Huge Adventure (2002) • Crash Bandicoot 2: N-Tranced (2003) • Crash Bandicoot Purple: Ripto's Rampage (2004) • Crash: Mutant Island (2009)|
|Cancelled games||Crash Bandicoot: Evolution • Cortex Chaos • Crash Online • Crash Team Racing (2010) • Crash Bandicoot 2010 • Crash Landed • Crush Bandicoot • Krome Studios pitch|