Even if I agree with the other posts in this thread, I'll ignore the quality of the frags and I'll give you some constructive criticism if you're looking to improve your content for future videos.
1) You have to stop slo-mo'ing every single pop-up or finisher airshot. Let the frags go on and sync it to the music naturally. If you do intend to slow down a POV clip, record at at least 120fps (although the standard is generally 240 or higher). Otherwise, slow down your smooths instead - record at a high fps (I personally use 960), and slow down to nearly 1% playback and still keep a fluid 60fps look. This will enable you to transition out of a frag easier than a 1-second-long smooth that doesn't add any value to the video.
2) Transition your clips better. I don't mind a fade-to-black intro/outro, but not every single frag needs a fade in and out. Learn to use Vegas/Premiere transitions, or simply do "hard cuts" without any transition to move between clips fluidly. This can be done through implementing smooths (see 1) or third person angles.
3) Sync the fragging part of a clip to the music, not a brightness/contrast flash. Look at 4:20 in the video. The frag already happened, the explosion was almost finished, and THEN the RGB split/brightness change happened - and the latter is synced to the song. There is no point in syncing those effects to the song when the frag has already finished. 4:28 is a better example of how it should be done - but try to avoid the jarring slow-mo beforehand.
4) When making smooths, have some motion in the them, but watch for when your character model is crouching (4:16). If you slow-mo your smooths, you can simply cut out the portions of the sequence where your character is crouching - and you can create simple motion effects with using speed/duration effects. Try to make more smooths like you did in the beginning section ( 0:29 - 0:34), those look good and should be emulated when smoothing airshot finishers or similar things.
5) Use the normal killfeed, or use a fully-fledged custom killfeed. People like to understand when the person gets the kill, and often times people like to see who got owned. Look at Googler's videos if you want inspiration on custom made killfeeds - CSS/GO movies also implement these. Despite your intention may have been to go for simplicity (or to hide lower skilled players), it doesn't get the point across. You can show a nameplate with the person in the clip AND their name in the killfeed.
5a) If you're using a custom killfeed, make sure it stays in the same spot throughout the video. Why would you move the killfeed from the top right to the top left for no apparent reason? (0:53 compared to 1:00)
6) If you have issues with the doorways like at 3:01, type "r_portalsopenall 1" in console to fix it.
Sorry for the ramble, but if you keep at it, you'll definitely improve with the fundamentals. Once you've got those down, you can create your own editing style. :)
I hope I've helped!