The game had several different logos during development. The fourth logo is the final one.
Hit & Run Explosions
Early versions had a generic car explosion without the remains of the car tumbling about. This is actually the exact same car explosion seen in The Simpsons: Hit & Run. Both games were developed by Radical Entertainment.
The Wumpa coins used to have a Crash image on them instead of the current checkered flag. If you look closely, you'll see that the image is a promotional render from The Wrath of Cortex.
- Crash's Trikee used to be a bit different. It used to have red stripes and the front was changed.
Some characters had each other's cars. Here we see Crash driving N. Gin's Doom Buggy and Pasadena's Le Chaux, as well as Pasadena driving Crash's Crikey.
The fat man from the "Bummed Out" Die-O-Rama used to be one of the wandering NPCs. He is also shown in the tutorial segment in these screenshots, where no one but Crash is supposed to be in.
Battle and Stunt Arena Signs
The big signs displayed here were eventually removed.
Pyramid Pass Stones
These stones aren't present in the final version.
Unseen Cars(contributed by Dtropy)
This promotional character profile shows a few cars at the bottom that aren't present in the game. These are Cortex's car and the clashed form of Crash's yellow car (here it looks like a tank, but in the game it has wheels with spikes on them, among other differences).