The search for a "highly compressed" version of Microsoft Office is a trap for the impatient. While the idea of getting a $400 software suite in a 50MB zip file is enticing, the reality is universally bad: You get malware, broken features, or both.
To understand the hype, you need to understand file compression basics. Standard compression tools like WinRAR or 7-Zip use algorithms (such as LZMA or DEFLATE) to reduce file size. Generally, you can compress an average program file by 15% to 30% without losing data.
Even if the software installs, highly compressed versions break the Windows Registry. You will open a document for a work presentation, only to be met with a pop-up: "Microsoft Office needs to configure itself." You wait 10 minutes. It finishes. You close Word. You reopen it. The configuration starts again. Forever.