There are more or less frequent discussions of bad science in movies, games etc. Damn, this computer is slower than my typing, much slower. It's much slower even than the eBox I have at home, from which I've once blogged. It's so slow I can't be bothered to look up the link to that certain post.
Anyway, bullets have low momentum and can't launch a dude in the air, lasers travel at light speed which is for all practical purposes infinite*, and sound can't travel through empty space. Neither can laser light scatter off empty space, so the beams should be invisible except where they hit something. It's light, not projectiles.
*). compared to practical lengths for spaceships and human eye response time.
So people like me praise old, well thought-out movies like 2001: A Space Odyssey, where there was no sound in space, no gravity on space ships et cetera. New movies on the other hand feature low-budget crappy CGI, all sorts of glowing beams, explosion sounds synced with space stuff blowing up, and Earth-like artificial gravity everywhere. Then I thought. Dude, you can hear the sound from a blast in space, because debree would be hitting your vehicle. But I'm pretty sure it would sound very different from fire crackers.