Appreciate the comment, but I want stress that the problem really is the computational complexity. (Or at least, computational complexity really is a serious problem.)
If everything in your world behaves like a bullet, physics is simple. If everything in your world behaves like a sword, physics is a nightmare. A lot of games with swords literally pretend that swords are made of bullets to get around this. No kidding.
To spoil my deep explanation: in the sense games are concerned with, a bullet is a non-rotating length-0 inertially-controlled sword. That doesn’t generalize cheaply.
If everything in your world behaves like a bullet, physics is simple. If everything in your world behaves like a sword, physics is a nightmare. A lot of games with swords literally pretend that swords are made of bullets to get around this. No kidding.
To spoil my deep explanation: in the sense games are concerned with, a bullet is a non-rotating length-0 inertially-controlled sword. That doesn’t generalize cheaply.