A game I like very much is "Drymouth". It's Freeware but has fully commercial quality. If you love games like Mario's Picross... try Drymouth! I can also recommend:
* Little Fanatasy (Freeware)
* Drains (Freeware)
* Jumpik (Freeware)
* Nibbler (Freeware)
* Sworld (Freeware)
* Sworld II (Freeware)
* ToyToy (Freeware)
* Ultima III v0.995 (Freeware, Remake made with permission)
* Tridball (Freeware)