First, if you're not an animation mentor student don't use their rigs. It's a sure way to not get hired. As far as the animation goes, your juggling part needs work. The balls float like they're in zero g space. Add some weight to them and use some arcs on the characters elbows and hands. It's very stiff, but is a good start. Your quadruped run is ok, but the characters head needs to move a LOT more than it is. It too looks stiff. That whole section is too long for my liking, but that's just an opinion. Cut it to a quick run, the tigress lying on the ground him coming up to her and her getting batted down. When she gets batted down, it looks like he's batting a mouse. He needs to put some force behind that and she needs to hit that ground hard. Or if it's playful, he needs to still put more force into it, but she should also fall down more gracefully. Fall into bed on your side a few times like you're trying to be sexy. That's what that would look like. The squirrel is ok, but I'd pick a stronger acting piece personally. Your first piece is ok, but I feel like you're over-acting the characters. Yes this is how the Marx Brothers are, however, it's a tad too much here. Why does he pull his hat off only to put it back on and continue to fidget with it? If he needs a prop in his hand, start with it in his hand and then put it on his head and have him end with him smoothing out the brim or something. That first piece is your best piece though. However, as I mentioned, if you're not an AM student don't use their rigs. (The only reason I'm assuming you aren't is because if you were, you probably wouldn't be posting on here and you also wouldn't be using other rigs. You'd be using their awesomely amazing rigs.)
It's a good start. Just start tweaking that stuff. Videotape yourself doing the motions and use it as reference (if you're not already). HTH and I'm not trying to be a jerk, just trying to help. 
Oh and I love the Marx Brothers.
