Yao there, you tend to make so many videos in such a short time Lol. What proteins do you take @__@ ? Jk lol, I like your potential yo!
So thing about this video is that its quite random really. Not just for the fact that its an animix, no since I do like watching this type, but the issue is the lack of dynamics throughout the entire video.
Your strong point is external sync (Synchronizing with the lyrics and vocals of the song) but your internal sync in underwhelmin (sync. with the beats and instruments) therefore your last 2 vids weren't as powerful as the 1st few. But i'm not saying that to make you feel bad Lol, no, just like last time i'm happy that you're trying out these new stuff so that you could master this style as well.
So what I suggest you focus on is either placing your clip @ where the music pace makes it feel right (synchronized with the beats) or instead of completely changing the clip at these moments you try having a clip where the character or whatever is making a certain motion that fits well with the beat. There are more ways of syncing internally, its all up to your creativity and ideas, but these are just the basic 2 most common methods.
The keying you mentioned was referring to near 0:19? and I noticed another one where you keyed the sky out. the 2nd case was fine, but in the 1st one I believe you should have adjusted the threshold parameters until you have no more dark pixels covering your clip on the layer beneath. Ya just that Lol.
Last point would be talking more about dynamics. When it comes action videos it is for the best to intensify the atmosphere as much as you can. I mean to just have some intensity. Since being more intense than the music is actually a negative.
To do that you need to gather the dynamic scenes. You see there are some clips (mostly in action/climax, moments of the anime) that contain more work from the animators than the rest. You know them from the interesting camera angle that dances around the characters, or the very cool motion that the objects in the clip are making, etc etc. Basically clips that look cooler Lol, and this is what we call "scene selection" in amv language, you need to give more thoughts to what scenes you use, and also to what scenes you put before/after, because here is where "flow" comes in the picture. The most important thing in an AMV (or at least according to me) is flow. Flow is basically the direction that all the clips are moving in. So good flow will reflect clips that work together in harmony once you place them before/after, each other.
So yea that's it for dis review Lol. Keep going! Chaw~