Now this is pretty awesome! I love fast percussion sequences and the drums in this where no exception, they where amazing! I love the subtle electronic elements at the intro and I especially love the hammering timpani rolls later on. Also, the chords you created with the brass and strings in the second section where so perfect! They added the right amount of tension needed in a chase scene, to give it that sense of danger!
However, I do have some problems. The strings in the first segment felt a little... weak to me. It's like as the notes get higher the velocity gets lower and it doesn't quite balance out right, I think it should be the other way around. It seems like they where made to build suspense but as it get softer the tension fades and it doesn't quite compliment the impact that the percussion is providing. I also think they could benefit from being layered with some heavier strings to give them a little more thickness.
I also didn't feel comfortable with the transition around 0:32. The strings just stop completely and it crashes into this percussive ambient segment. Don't get me wrong, that segment super awesome! It builds up nicely for the brass to come in and I love the effects you used to provide this jungle-like atmosphere. My problem is it just kinda comes in at random and feels disconnected to the first part and in a track like this everything needs to flow nicely and have each segment morph into each other. It may help to have the strings continue with the same rhythm but take a more atonal role or something like that.
Apart from that though, it's a really solid chase theme! My points where pretty nit-picky since the mix and over-all composition was spot-on. It sounds really professional! 4 stars!
P.S. I also want to add that it reminds me of the lost world music in sonic adventure :3 one of my favourite soundtracks and this really brought me back :) well done!