It isnt bad, the animation is good, but like you said, it started as a comedy and then it ended up being a dramatic movie. At the start you have funny situations (the camping guy adn the "Get them tiger" with the mexican spartan) and all of the sudden it gets dramatic. It doesnt work all that well, you should have made a comedy movie or a dramatic movie instead of mixing both.
You could mix both and still have a good movie but in here the mixing is just over time, the start is fun, at the midle there is a noticeble cut of direction and it is drama all of the suden.
Also, your comment on durge's review isnt all that great, it is understandable that he thought about having a joke near the end, a la "Wainting for the Bus" and its sequel that base around a very dramatic situation with a lolz at the end to make the viewer think "lol wtf?".
PS: Dont make a "Dot Dot Dot" out of this, lol