Yesterday I got curious and started making a test game with Gamestudio. In the game, the player entity uses a "collision mask" entity, that's shaped like a box and has its POLYGON flag set.
Unfortunately, I discovered that when other entities use c_move() for collision detection, they *always* perform collision detection as an ellipsoid, regardless of whether or not their POLYGON flag is set.
wwwwwhhhhhhhhhyyyyyyyy