I won't comment on the aesthetics, but only on the layout and messaging. (There are better designers here than me.)
You could do a bit better job on the text as some is a bit longer than it needs to be. The layout is excellent, but you're not taking full advantage of it.
At the top, your last line should be more like:
What it does:
That sets things up. You could even do that in a smaller blue font than in the title. Use whatever short language works best, e.g. "It tests:" or whatever.
The 4 grouped areas have a lot of impact, and work like bullets - very nice. The black/gray text is a nice touch, but make the black text shorter. e.g.
Elevate to admin privileges.
Run as a service.
Run as a desktop application.
Just examples there. Shorter is easier to read, punchier, and people will make fewer mistakes. (Most people don't/can't read.)
Using the active voice was the right choice. Keep that.
Check what you mean by "switch", as it implies that the program can do that on the fly, which I would not expect.
The bottom text is confusing. I'm not sure what's going on there, but then again, I don't know what the application is supposed to do, so I could be off-base.
I like the bottom buttons. They are clear. The chevron also helps indicate forward motion.
Overall, I think it's pretty good. The linear layout leads eventually to action at the bottom, which is what you want. I think you've done a good job there.
It's hard to program and do design and do writing and do... You eventually get distracted by one aspect, and neglect another. Been there more than once. Have the mistakes to prove it~!
Just my $0.02.