how do I reduce number of .vmdk files before zipping

I am running VMware Workstation 12 Player (12.5.9 build-7535481) on a Windows 10 machine. Before zipping the image to distribute to students who will try to find and fix security vulnerabilities, I see that I have a number of .vmdk files Is there a way to reduce the number/size (27.2 GB) of these files?

I used VMwareToolboxCmd.exe disk shrink utility on the guest image and received the message "disk shrinking complete." My compressed file size, using 7zip, is still a rather impressive 14.6 GB.