How to play Space Crusaders on Mac

Crusaders Of Space: Open Range is a single person, shareware, space shooter of the fixed screen variety. It is the sequel to the game Crusaders Of Space. The game consists of two missions/episodes each of which contains five ten-level missions that can be played on three difficulty settings. As the player progresses the opposing enemy ships become progressively more numerous and harder to defeat. The player has only one life with which to play this game and achieve a high score. However as they progress they can collect weapon power ups and shields and when they take damage instead of dying instantly their ship loses one of its power ups. In each mission the last level, level ten, is special in that missiles cannot be used. Some of these levels have an end of level boss while others have an extra hard combination of enemy ships.