A MDF is an Alcohol specific format, It's like the default Alcohol 120% Image ripping default. I think it's commonally used because it generally rips everything.
Daemon tools is what I used to mount the image, and then I played it in ePSXe (don't feel like going through the trouble of burning it, pulling out the hardware, etc.). For some reason, the game locks up when I go to a certain level. I forgot the exact name, but I'm pretty sure it wasn't in the final game. Does anyone else have this problem? By the way, thanks for sharing .
Yeah, I think some (at least one the Concrete one) causes the beta to lock up, presumably because they were either test levels and removed or not yet implemented (and never implemented as it would seem).