The CD-ROM image is available on archive.org along with a pre-packaged playable version. The only way to view the intro sequence as intended is to mount the disc image as its own drive within DOSBox with the IMGMOUNT command. For example:
IMGMOUNT D "C:\the full path to the CUE/ISO file" -t iso
At that point, you do not install the game to the C drive in DOSBox, but you play it directly from the disc image, making sure to run either L3CD.EXE or L3CDGUS.EXE depending on whether you prefer SoundBlaster or Gravis UltraSound audio for the intro (and whether you have GUS enabled in your config file.)
Unfortunately, I can't seem to get the intro music or game sound effects working no matter what my DOSBox audio set up is, no matter which executable I run, and no matter which fork I use. Will update when I figure out a way to get that working. I have not tested the pre-packaged version yet; perhaps it works just fine.
IMGMOUNT D "C:\the full path to the CUE/ISO file" -t iso
At that point, you do not install the game to the C drive in DOSBox, but you play it directly from the disc image, making sure to run either L3CD.EXE or L3CDGUS.EXE depending on whether you prefer SoundBlaster or Gravis UltraSound audio for the intro (and whether you have GUS enabled in your config file.)
Unfortunately, I can't seem to get the intro music or game sound effects working no matter what my DOSBox audio set up is, no matter which executable I run, and no matter which fork I use. Will update when I figure out a way to get that working. I have not tested the pre-packaged version yet; perhaps it works just fine.