I'd probably ask them something that'd annoy them, such as why Munch had to suck so hard, before grilling them over not developing for the PC. :P Yay.
But no, if I seriously ever met them, I'd thank them for making such an awesome game series, then I'd talk to them about thier creations and about how some things in the Oddworld universe came to be. I'd like to know where Citizen Siege is going and what their plans are for Oddworld if CS is successful.
