The bonus material includes some early photo-realistic images, including a vase that morphs...

 

... and a transparent head. Pretty advanced stuff for 1981.

 

The coolest bonus stuff though is a short CGI clip done in 1978 of some X-Wing fighters.

 

For 1978, this stuff was jaw-dropping. ILM was impressed.

 

But apparently not quite enough to commit to using CGI... yet.