Welcome to the org! Glad to have you with us. :3
For early AMVs goes, you did a pretty nice job. You really captured the fun and romantic aspect of the song. But there were a few problems with it, which is what a lot of early AMVers do.
I liked some of the colored borders work that you did, because it felt like it was really fitting. But when you did it during the "The World Only God Knows" and the "Aramagi SS" parts, it wasn't as effective because it wasn't as tightly synced, and felt like it was more slapped on and less polished.
You overkilled a little on the fades, and lip flap was a serious problem. Fade wise, I think this AMV could hvae had some more hard cuts and perhaps some pans/zooms during the more fast paced parts. Lip flap wise, it was very distracting. I think you should consider masking it out, or picking scenes that don't have characters talking.
But it's a cute concept, and I got what you were going for. I thought you did a nice job transitioning between the different anime, but maybe consider mixing them all together instead of going from Anime A - Anime B - Anime C - Anime D, putting them all together during the whole song? It's ok to mix them all together and blend them.
Also, during Aramagi SS, the scenes were VERY static [I.E: the characters didn't move as much], and weren't as entertaining to watch as the previous two anime were. So maybe a little scene selection work here might have been nice.
Anyway, again, you had a cute idea, but needed a little more work on the execution. Again, welcome to the org! I hope you stick around! :3