Jetpack was an immediate hit when it was released in 1993, and a cult following grew internationally. The built in level editor is one of the most popular features - over 1000 levels have been created. Jetpack was the top seller for both publishers that carried it (Software Creations and Impulse Games). It is now available as freeware and all speed problems on pentiums have now been fixed.
You can have full access to a wide variety of levels here.