It's ok
I get the idea behind this, and it's a kind of funny one, but the animation itself is suffering from problems.
First thing's first. Get a preloader. They've got some free ones here that you can alter to your own means if you so desire. With a file this large it's really necessary, otherwise it won't load all at once and things get ridiculously laggy.
Alright, now for the actual animation. In my honest opinion, you need to put more work into this. Sonic's run is far too slow. It looks like you shot his feet on twos, but his feet should be moving at an incredible speed, not a slower one.
Mario looks overly tweened. His feet look like they're gliding across the ground rather than walking on it. Animate it yourself and put some weight on it. Trust me, it's not that hard and it'll add a lot to your animation.
Link's death was the funniest in my opinion. I can't give you much advice because very little was animated there.
Snake's wasn't all that interesting, but win some lose some, right?
Your backgrounds are unimpressive and bland, a little bit of detail goes a long way.
My last piece of advice: I haven't checked out number two yet, but what I can tell you is that we've all seen video game characters get killed before. Be as creative as you can with their deaths. Sonic getting nailed by Robotnik? Not that funny, we've all had it happen to us within the game. Mario falling to his death, kind of funny, a bit surprising, but we've all seen it happen. The reason Link's death works so well is because it's something new. A lot of these deaths don't differ enough from what happens in their respective games, so they're simply not that interesting to watch.
I'm sorry. Looking back on this review I realize that I've said nothing positive. Your short was kind of entertaining, but it could use some serious work. It's not hideous. It is watchable, it just needs something to set it apart from the rest of the crowd.