I don't want to sound mean, but it's the truth. sorry i can't tone it down to a 'softer' understanding. Just the way i judge.
Over-used shadow border effect
scrolling text is a very ugly color. the purple and yellow don't match.
Don't use drop shadow on text .
don't use that sun rays effect too.
you used 3 horrible effects in 1 minute seconds (no offense)
also, intro's should never be more than 1/4th the length of a montage. your intro was already 1/2
next time, don't keep 1 free camera clip of you going around the map, make it like a track-dolley like scrolling around the map split into different clips
the intro would've been better with C4D text or just text on the walls, without the black shadow outline, without the sun ray fx, and without the single shot
You need to get new sniper SFX (sound effect) or stick to the one that came with the game
the one you put didn't go well with the calming music and you didn't sync it well
don't put it dead time (like 2+ seconds between kills because it really makes the watchers lose suspense and rids of all wow-factors
don't ever do that scrolling text again in any montage, it never works out (referring to 1:32)
don't subtitle what happends in the clip (no scope, quick scope, headshot etc; )
don't use transitions either, just let the clips go together. the only transitions that should ever be used are fade out, fade in and flash.
You need to back away from using stock effects of sony vegas
get new sound effects
practice syncing better
killing dead time
working on fading in and fading out.
sway away from other transitions
try to color correct it too (look up some call of duty color correcting tutorials on YT)
I said Call of Duty because they have good color correction tutorials