I'll grant you the first point, the whole game is centered on space travel simulation, but it's also the only game I've seen that handles what you're describing. You definitely need to consider atmospheric density though. Managing your speed, angle of attack, and parachutes to avoid overheating is one of the major skills you learn while playing. Some are Earth like (Kerbin), other are thinner (Moho), and some are surrounded in an atmosphere so thick that it makes any return mission a huge achievement (Eve).