What's the difference of 7z to exe files, which is much easier to extract?
Viewing post in Caliross, The Shapeshifter's Legacy comments
The exe file should be easier to estract, in the sense that you can run it on windows and it will do everything on its own. The 7z file is for people that are having false positives with antiviruses or people that want the files to try and run the game on their phones, but you need something like 7zip installed to open the archive in that case. Note that to run the game on the phone, you'd need specific programs and to follow certain procedures.
You also need to install the RTP (only once) it's linked near the bottom of the page.