Hey!
I made a couple of little bookmarklets to help you sort out which locations you've been to and which achievements you've gotten. I have them at joefriedl.net/lab/bookmarkl....
The Location Helper adds little "Check" links to each zone at glitch.com/locations that, when clicked, crosses off each location you've been to. It also adds a "Set as Destination" link to each one for easy navigation! Source on GitHub.
The Achievement Filter fades out all the achievements you've already gotten at glitch.com/achievements. That one's much simpler. Source on GitHub.
You're free to use, modify, and distribute all my bookmarklets and pretty much anything else I make. Let me know if they work for you, or if you can think of any improvements or changes you'd like to see! Thanks!