Caveat: I have always hated Martin Short. I find him annoying, semi-retarded, and blame him for the Phoebe-Cates-career-killing "Drop Dead Fred", even if he was not even in that film. However, Short was quite amusing in this one.
"Innerspace" has Dennis Quaid shrunk down to be injected into a rabbit. Whoops! He's stolen by the villain from "UHF" and injected into Martin Short instead, who then must save Quaid with the help of Quaid's girlfriend, the pseudo-lesbian Meg Ryan.
Short's quirkiness worked for this film. I mean, goodness, he has a little man inside of him. And he works well with director Joe Dante, a Steven Spielberg protégé influenced by Bugs Bunny... his comedy is best reflected in "Gremlins" and "Gremlins 2". How he got to be a master of horror is beyond me (though one would assume from "The Howling").
The shots inside the body were interesting (like the "Body Wars" ride at Disney World), and Quaid was a great pilot for the adventure. I could have used less Meg Ryan, who seemed to be very unnecessary to the plot and her allegiance was unclear.
So um, yeah... it was a fun romp... watch it.