You can play it online in the JaC64 emulator using Java Web Start. Use your arrow keys to guide the bubble through the maze. Avoid the hazards and find the five keys to unlock the exit.
You can also download the D64 disk image file bubble escape.d64 and run it in VICE x64 or some other Commodore 64 emulator.
If this game doesn't seem too impressive to you, try to remember, it's only two kilobytes of code! These days you can't even sneeze in less than a megabyte.