I am extremely happy to report that the 4K disc is amazing, TOP honors to Severin! I've only ever seen this on DVD, and watching it in 4K was like experiencing it anew (much like how I felt with Arrow's DEMONS 4K).
This is a dark film, as most of it takes place on Christmas Eve, so I was afraid they might be tempted to DNR the natural grain out of the film - wisely NO DNR is present, and the application of HDR to both the colors and the contrast of the film is expertly done imho. Much like HIGHLANDER, from what I can tell this has never been a good looking film, but congrats to whoever remastered this as I think this will be the best it ever looks.
I did a quick comparison of the 4K disc to the included blu ray disc, and while the blu is certainly a leap above the DVD, the 4K bests it in every aspect.
The audio is excellent as well - I'm guessing the original audio was Spanish 2.0, but I chose the Spanish 5.1 mix and it sounded fantastic. It also has a 2.0 English dub for you heathens out there
The extras are the icing on the satanic cake: an 80 minute professional documentary which by itself is a must have for Iglesia fans, a separate 30 minute interview with the director, 2 cast and 1 crew interviews, a really cool short noir film (12 min) by Iglesia, and trailers.
If you're already a fan of this film, buy with confidence and enjoy.