General form/technique is good- wouldn't worry at all about differences in L/R symmetry, because those are inherent in running.
Gait (variables such as step rate), kinematics (variables such as knee angle), and kinetics (variables such as GRF) all have a "range" of acceptable values, and from a gait and 2D kinematic, you don't really have a glaring need to worry about. As mentioned, a lower leg posterior view can assist with the structure and function of your foot and shoe relationship, but given the short clip and single speed of the video if that is your initial footstrike pattern, your foot and shoe function are probably pretty good (not a knock on what you did- the majority of folks who look at an isolated picture or video at one speed are seeing maybe a small fraction of the injury risk potential or performance). Absent of continuous running metrics (such as an accelerometer) or variables over a range of speeds below and above your race pace, making a judgement off of a short video is more an analysis of style rather than technique.
From a coaching aspect (after picking apart the video in software platform- so this is said more of the art vs. the science), would say that your stance and swing phase reversal is a little off (purely subjective- but after doing hundreds of these...)...would probably say to include one or more days a week of steep incline hill reps that are about 10-20m in length as a part of your cooldown. It needs to be steep (think 12-15% on a TM...but these are always better outside so you can easily do an active recovery). Focus on hip/knee drive and ignore your foot altogether...if you try and focus on a "powerful push off" you've already defeated the purpose of the repeats. Walk the downhill. Each rep should only take a few seconds, and 4-6x is good.
Good luck in your race!
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