On a whim I started up Highway Hunter yesterday, a top-down shooter I used to play the shareware version of.
After playing the two, honestly disappointing, commercial episodes I wonder how often it was that the best content was put in the shareware version?
There was plenty of asset reuse, the two new power-ups were pretty meaningless and some of the bosses could be defeated by only holding down the space bar. The shareware levels were far more difficult.
Great music and graphics though!