Galax is a popular clone of the classic arcade game Space Invaders remade for Palm OS.
Note that Galax supports both grayscale and color displays, but not high-resolution ones.
Versions of Galax prior to 3.0 were released as shareware, while 3.0 was freeware. Have a copy of 3.0 to share? Click here to submit it! Otherwise, it is recommended to use the patched version of 2.2b which removes trial restrictions, available below.
(Based on user feedback)