I'd be interesting to know... probably C++, as I doubt anything written in VB would port to the Mac well. But I could be wrong. Either way, C++ is sort of the norm for programmers, unless you're doing web apps (or have some crazy interest in Java o_O).
What I'd like to know is the coding algorithm for the
physics of it all... how the shot is fired, is affected by gravity and wind, etc... there's gotta be some crazy physics equation in there somewhere.

Maybe I should go before I relive highschool physics class nightmares. XD
Though I did once beat my physics teacher at PT... shareware version, that is...