Adam Sandler’s star appears to have dimmed significantly, after “Pixels,” a slice of arcade game nostalgia, opened to a disappointing $24 million at the domestic box office. The critically derided comedy finished up just behind Disney and Marvel’s “Ant-Man,” which picked up first place and $24.8 million in its second weekend. That marks the weakest chart-topping performance since April 24 when “Furious 7,” then in its fourth week of release, bested all challengers with $17.8 million.