I am up only to up to 2.37...
First of all, the system decides to forget my progress with utterly frustrating frequency. And every time I download a Lab or other document there is no way to go back to where you were other than restarting the course. I am using Chrome.
Second of all - what kind of "course" is this? Look at 2.37, it is a bunch of commands. You're basically told to mindlessly type them in. There is absolutely no explanation about why the syntax is the way it is. It makes absolutely no sense.
Third of all - an amazing amount of the commands simply don't work the way they are presented. I can upload examples. You have to leave the course and go to the Internet to actually make the suggested changes. I run Centos 7 in VM Workstation 14 Pro.
In a nutshell - basic navigational issues, no best educational practice to explain why a command's syntax makes sense, and bugs that point at very poor quality control.
I honestly can not recommend this course to anyone I know.