I'm a packrat, so finding the old sprites wasn't that hard. Truthfully, there are even older ones completely lost to time on some floppies somewhere... but those were mostly just sprite edits.
I made the old sprites using MS Paint Vista. Tower Shadow was the first game idea I really liked that I started making art for. The kid shown above has his shadow taken over by a shadow creature and thus has to solve light-based puzzles and fight creatures to save his family while traversing his home, a big mysterious tower.
I was about 13 years old when I made that sprite. It was kinda painful looking at it and knowing I once thought that was good. I'm happy to have grown a bit since then.