Shareware is where an software author uploads a program (here a game)
to a place, and people can download them and play them for free.
However, this may be only a demo version, and the author expects you to
buy the full version if you really like the demo version.
These are pretty good, but sometimes there is a long, long download
time involved for a game that is very short and not worth the download
time. However, the large selection involved usually makes up for the few
bad games.
Here are some links to a few shareware
sites that I think are good:
This addictive game will test your skills on over 180 mind bending levels. Lasers have never been so fun! Tutorials get you started, but expert levels will test any genius!