Marvel released the new “Super Hero Augmented Reality” app Thursday, in advance of the May 4 release of the film Marvel’s The Avengers. But this app comes with a twist–the only way to win is to visit Walmart stores across the nation.

“Walmart is bringing this summer’s most anticipated blockbuster into stores through a first-of-its-kind augmented reality experience which bridges the gap between the physical store and mobile gaming,” says Seong Ohm, senior vice president and general merchandise manager for entertainment, Walmart U.S. “We’re committed to creating engaging and fun experiences at Walmart, and we’ve tapped different areas of the store for movie fans to interact with the mobile app while shopping the more than 600 Marvel’s The Avengers merchandise available.” 

Here’s how it works: the downloaded app (available at the iTunes App Store and the Android Market) comes with instant access to Hawkeye and his superpowers. But to win the game and defeat Loki, players must visit Walmart stores to unlock the five remaining Avengers. Players unlock additional Avengers by aiming their smartphones at specified signage in various departments throughout the store.

Players also have the opportunity to activate the Photo Capture Mode, which will allow them to take pictures with their favorite Avenger.