Free online version vs. purchased offline version.

The free online version is restricted to predetermined puzzles of three sizes. The purchased version generates thousands of puzzles anywhere from 5 x 5 up to 33 x 19.

The free online version is kind of small. The purchased version can be expanded to full screen.

The free online version only stores scores on you current machine. The purchased version allows registered users to submit their scores online for all sized puzzles. (There are groups of sizes for easy comparison but all sizes can be submitted.)

The free online version runs online at www.cdotspace.com/circuitry. The purchased version runs from your machine and does not require an Internet connection except to submit your score or check for updates.

The free online version is free. The purchased version costs $20.