Air Defense by Darel Schartman is a shareware program. I believe this is a high quality game. It has been thoroughly tested and beta tested on other BBS systems before this public release. If you and your users enjoy this game and you would like to show support for future projects, please send a $10 donation to: Darel Schartman 5053 Clayridge Dr. #207 St. Louis, MO 63129