Both movie theaters are AMC, and are specifically located in the town limits of Westminster. (You can find numbers of other theaters at various other nearby Denver local towns to pick from too.)
Listed below are both movie theaters in Westminster, including a little bit of advice on each:
Westminster AMC Promenade 24 - This is a good theater to pick for movies in Westminster, CO if enroute either to or from Boulder, since it is located close to the Boulder Turnpike. Per several reviews that I read, this is a great “go-to” theater, having excellent resources, including an IMAX screen and four theaters in total. This theater is known to also have soft and comfortable seating.
AMC Orchard 12 - While this cinema is “not the largest,” it is still known for excellent quality sound and picture. There is a small IMAX theater in this establishment, is known for comfortable seating, with a clean and pleasant environment. Per the reviews that I studied, this is a good theater to attend if someone doesn’t appreciate fighting crowds - generally it isn't overly crowded and it is a pleasant spot to see a movie. This theater is located further east than the Promenade (above), just off 144th Avenue and Highway 87.
As earlier mentioned, there are additional movie theaters nearby and are perhaps closer to one’s location if in the Denver city area, nevertheless the two theaters in the above list include the highlights of what's specifically to be found in relation to movie theaters in Westminster, CO.