It certainly is. It's basically a drop-in replacement for a SCUMM interpreter program; which means that it emulates (at a very high standard) the original functions of the original SCUMM interpreter.
Very similar to something like a SNES emulator actually, the main difference is that its interpretation of the code is not necessarily built around creating a complete working software "copy" of original hardware functions.
One thing that SCUMMVM does not emulate at all is the save-game function - instead they use their own, and as a result are completely unable to save or load original save games.
Last edited by plamdi.com; 08-22-2009 at 08:12 PM.