What's cool is that as I made these games I kept wanting to add more to them (interactivity, sounds, etc) so I ended up doing some scripting as well.
As a 12-year-old, this was amazing - my first introduction to "programming" but I didn't know that at the time.
As an aside, I sold it to my school mates for 50p a copy. When they asked why they couldn't just copy it themselves I told them I'd installed DRM on the floppy disks.
They believed me.
What that kind of a stack enables is potential. So you're happy with your app. Take what you already know, learn about a server and a client and make a scoreboard. Now you understand client/server you can make it collaborative. etc.
jQuery makes even that learning curve a lot easier (e.g. $('.text-box').text() instead of whatever even hackier stuff I was using back then).