Maelstrom is not OS X native. Maelstrom requires a Macintosh running OS 7, 8 or 9. At the present time, we have no plans to port Maelstrom to OS X.
Maelstrom's sequel, Deimos Rising, is OS X native, and has been ported to Windows. Check it out: http://www.ambrosiasw.com/games/dr/