Everything fails equally and laughably

Changing Ker into a villainous lackey instead of an ally.
"Debating a troll is like trying to play chess with a pigeon" Modified Quote

John Travolta's high pitched voice

That is a good one.
"Please vote to preserve the unique character of Warren…" - Robert Duvall

The sudden "We're going to destroy their home planet" plot development and how remarkably simple it turns out to be.

The utterly retarded tilted camera shots. There is a reason people don't do this when making films; it looks beep

Forrest Wittiker

Thousand year old Harrier jump jets starting right up after sitting for those thousand years. LOL where to even start on this abomination

Yeah, it certainly is humorous and comedic, but only from our perspective.. their actions and the way they conducted themselves was largely due to their characters ego and overestimating their ability to outsmart the "man-animals".
As for the special effects, irrelevant, they were adequate and served the purpose.
As for the harriers still working after all that time, yeah, I imagine that's unlikely.

The special effects of the movie aren't really that bad. It's mostly the nonsensical plot and the pretty bad acting. Watch it as a comedy though and picture Terl and Ker as the stereotypical bumbling cartoon bad guy duo and it becomes something completely awesome.