That's very strange, what you have described bellow does sound like corrupted files. I recommend following the steps bellow :
1. Redownload the game
2. Place the archive in a drive with enough space (at least 4 gb free)
3. Use 7zip to unzip , selecting unzip here (so that it doesn't cache them in C: drive)
If there are still errors you could try disabling any antivirus software (although this was never needed before, and the archive was not modified for more then a year).
The gameplay should look like in Gameplay vids (can be seen above in main post), if it looks different then there has to be some errors.
I hope this helps,
Cheers
~NK