Apple II RGB Monitor Problem

["Tempest" <tempest@atariprotos.com>]

I recently picked up an Apple II RGB monitor (not the IIgs one) and the
special card that goes with it.  It works great, in fact some games
like Kings Quest actually look better on the RGB monitor although the
colors seem a bit off (the pink flag on the first castle is almost a
lavender for instance).  However when I tried Airheart I was shocked to
see that the whole game was B&W!  I've seen this kind of thing before
on my Atari XE when I tried to play games that used artifacting using
an S-Video connection (since it separates out the Chroma and Luma), but
never on an Apple.  Does this mean the RGB monitor is basically an
S-Video connection?  If so, how come Airheart looks ok on my IIgs with
an RGB monitor?