Probably would have been better to start a new thread. Here is my guess about your issues.
 
I would imagine there are only two Z3TA+2 installers now, one for the PC and one for the MAC. So it makes sense if you have two line items, they point to the same installer. After installing Z3TA+2, click on the logo in the upper left-hand side of the UI to display the about screen. The version number is on the bottom left-hand is side of the about page.
 
The Z3TA_2_Free_Mutant_Patches.zip is ~17KB.
The Z3TA_2-Polybius.zip is ~88KB.

Thank you very much for your response, I was a bit concerned that my question may have been a bit confusing...
 
The installer I downloaded is the version 2 according to the name of the file, but you are right, the version actually installed is the 2.1.
 
The Z3TA_2-Polybius.zip I have is 88KB, so it seems OK.
 
My Z3TA_2_Free_Mutant_Patches.zip is 9KB and not 17KB... and once unzipped, the final folder <! FREE MUTANT PATCHES>(without the install doc, MAC_OS folder and so on) is 51 KB and it contains :
- 3ncanti Lazer.fxp
- Desert Window Plus.fxp
- Droplet Gates Plus.fxp
- Dutchmaster.fxp
- Electric Beam.fxp
- Matrix Voice Plus.fxp
- Noteon IDM Plus.fxp
- Psychedelicious Squelch.fxp
- Sludge Revenge Plus.fxp
- Wub UK Plus.fxp
 
Is is quite strange we don't have the same size for the mutant patch, because I had no problem to download this one... maybe it has been updated ?
 
 

scookProbably would have been better to start a new thread. Here is my guess about your issues.

mmmhhh... yes, you must be right...

Yeah, you got the right free mutant zip containing 10 programs. I did not realize I had bundled the "How to install" rtf with the original free mutant zip. Sorry for the confusion.

It's fine ^^
 
It seems I have all the parts :)  Thanks again for your help !