This short, sweet Google video mashes up Super Mario Bros with Psycho Crusher, in an hilarious example of why different games have different physics. Link (Thanks, Fipi Lele!)
Update: Shadow Government Supreme Commander sez, "That video was created using the MUGEN game engine. MUGEN basically allows you to import characters from various 2D fighting games into a single roster and allows you to edit those characters into different backgrounds/levels - allowing for awesome mashups like the video you posted and awesome matchups like Homer Simpson Vs. Mario or any other combination you can imagine... And for yer extra added enjoyment, Here's godzilla smashing up the same level (also thanks to MUGEN)."
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