How to play Platypus on Mac

Platypus is a fast, frantic and fun arcade-style shoot-em-up. The vast continent-spanning city of Collosatropolis has finally reached the limits of its expansion. Tall buildings cover every available space. The air is thick with smoke and poisonous chemicals. Parking is a nightmare. The Collosotropolan leaders have decided the simplest solution is to invade the neighbouring country of Mungola. They don't anticipate much of a struggle - Mungolans are simple, earthy types without much love for industry. In fact, Mungola's entire defence force consists of a single squadron of fighter planes - the venerable F-27 "Platypus". What possible threat could a few antique aircraft be to the mighty Collosotropolan Battle Fleet...? To the Mungolan people the venerable F-27 "Platypus" is their last best hope for freedom!