It was a great freebie, but does anyone know if there was a DTS version produced (or even vanilla 5.1)?. Stereo is a bit basic to do it justice.

Hi there.
Unfortunately only the 2.0-2.1 Stereo Speakers/ Headphone format is available as the original digital .mp4 sound file, embedded in the image.
But you can further try to simulate a DTS/ 5.1 surround sound format, through your playback software, if your system's build-in motherboard sound chip/ dedicated sound card supports it, and if you have the required harware (speakers/woofer e.t.c.), to set up around your room.