A good puzzle game is based on a few simple rules but is infinite in complexity. This describes Elimimatch perfectly.
Lemonade Tycoon (2003)
This sim is deep and complex, with hours of gameplay for the dedicated sidewalk lemonade hustler.
Despite its extreme simplicity, Jamdat Bowling is the type of game you'll play again and again.
Top Gun: Air Combat
Thanks to its challenging and exciting gameplay, Air Combat is still a very entertaining romp through the not-so-friendly skies.