The phrase "good horror flick" is a colloquial expression used to describe a horror movie that is well-made, entertaining and enjoyable. It implies that the film has successfully created tension, suspense or fear through its storytelling, cinematography, special effects, acting or other elements typically associated with the horror genre. When someone says they enjoyed watching a "good horror flick," it means they found the movie to be scary and thrilling while also appreciating the artistic merits of how it was made.