For the first gun barrel (the default video on your channel):
Take it easy on the compression! You're really smashing the detail out of the audio. It also sounds like you're punching the hell out of the highs and lows while killing the mids. That's a mistake a lot of people make - i.e. the smile curve.
Second gun barrel (going down the list of uploads)
You're still putting way too much emphasis on the highs. This one specifically has ONLY highs. Fill up the spectrum and this one has some potential.
Gun barrel 5:
It doesn't sound quantized to me, but maybe that was intentional. Idk, it sounds pretty messy in terms of timing. Sorry, don't have much I like about this one.
Quantum of Solace car chase:
It started out nice, but as soon as the action started, I felt like I was in an 8 bit video game. I don't mean to discourage you, it could very well be that your samples and synths simply suck hard. From everything I've heard, you really love that high end of the spectrum. Balance it out and give the mids and lows some love.
Sorry for coming across negative, but keep doing what you're doing man!