I liked the more methodical approach to gameplay in this one. I could see this being a really interesting strategy game if movement were incorporated and more units were involved. I liked how there were two guns for each mech to use that were independently controlled. The ability to scroll forward and backward in time to see where the turret position would be at that point was nifty too.
The UI was a bit cluttered and hard to read though -- I'd suggest using arrows rather than yaw/pitch to aim the turret/mech body. Also, it was hard to see where a bullet was going to impact. Clarifying that a bit more would really help make it easier to pick up.
Definitely a cool concept though, and the background music was a great choice. Felt like I was making tough strategic decisions in the middle of a battle. Good luck with future development. I'll be interested to see where it goes :)