Crash Bandicoot 2: Cortex Strikes Back is a platform game and the sequel to Crash Bandicoot. It was developed by Naughty Dog and published by Sony Computer Entertainment for the PlayStation video game console and released in 1997. [Info from Wikipedia]
In the beta screens and videos there are some interesting beta stuff that were removed or changed: 3 levels that are shown (one with snow, the space one and another one in the sewer) are not used in the final version, while the warp room was really different from the one that we played. Even the HUD was changed (similar to the one from the first game), there was a Jetpack enemy (removed), a couple of animations and the design of some of the levels (like in the Turtle Woods) were not like the final version. For more informations you can check the Crash Mania website, that has donate these images for the U64 Archive! Thanks a lot to HPZr :)
In the second video below, OKeijiDragon noticed some more differences:
From what can be made out, the video shows vast differences compared to the final. Most of the levels layouts shown don’t resemble anything we know, except maybe the Jet Pack levels. Details include Crash 1’s HUD, and Easy / Hard poll in the middle of a Road to Ruin-like level, suggesting alternate routes were planned for levels.