I think it helps (not that the person is, but he's a limited actor) that Mr. Piper is playing a pretty stupid character. By which I mean, the protagonist does plenty of awesome stuff but his only solution to every problem is to blindly rush towards danger and kick its ass.
And there has never been a better idiot hero then Nada (here's a hint to his intelligence, he's named Nada). Almost every problem he encounters could have been solved with a more thoughtful approach, but fuck that shit, you're gonna wear those glasses or you're gonna eat this trash can. Maybe only Kurt Russell at his Jack Burton-ist could have played the part, but I really can't imagine anyone else in the role doing it better. Who else could so embody a charismatic, invincible blue collar dupe?
also, I keep meaning to grab a copy of this. I best hurry before it becomes too much of a rare item.

that's right, two hundred and eight pages of scholarly discourse on They Live. Damn right the movie deserves it.