This is somewhat decent
The voice-acting has a lot of room for improvement. Most of the line-deliveries feel very monotone, and don't serve their characters that well.
The Hippo Drill Sergeant for example, she sounds very timid and quiet, but by her character design and in the way she is used, you would expect her to sound tough and intimidating. I think if you made her talk very loudly, and gave her a somewhat raspy voice, her voice would fit the character much better
I'll be honest, you did do a good job of replicating the look of an old, degraded Looney Tunes cartoon. The film grain filter you used, along with the occasional scratches, and the frame moving up and down, do a really good job at making this look like an old film that someone found lying around in their basement, it's a very lovely effect
I would recommend giving your characters unique dialects that fit them. I think the hippo should speak in a very demeaning manner to her soldiers, referring to them as "ladies" or "maggots" and speaking in short sentences. This would really make her stand out among the other characters and show how intimidating she can be
I apologise if I've been overly-critical, but I am so critical because I love the idea of a Looney Tunes inspired cartoon with a female lead, it's not something I've seen done often and I genuinely hope you can make something great out of this =]