shareware can work but marketting is your perenial problem - you will only keep selling whilst you keep actively marketting. Particularly if your product is a game as opposed a utility.
If the game is good enough for shareware, then consider getting a publisher instead. If it is not good enough for a publisher, it will probably never do well as shareware.
Shareware is quite profitable when you have a niche market that is not commercially orientated. Such as
http://www.battlefront.com/ who's games would never do so well on a shop shelf but are relatively timeless in that they keep selling for a long time via Shareware.
Pneumatic Dryll