Harry Potter and the Deathly Hallows: Part 1 is an adaption of the movie of the same name. The player takes the role of Harry Potter on his quest to find the Horcruxes; the source of the villain's immortality. In contrast to the former games based on the franchise this is a third person shooter. The levels portrait key moments from the movie.
But of course Harry does not use real weapons; he relies on his magic wand to mow down the enemy hordes. He has different magic spells to his disposal; both offensive and defensive. The offensive spells are similar to regular weapon, e.g. expulso acts like a MG and stupor like a gun, and the defensive ones are used to turn enemies against each other or create cover. The latter can be useful because the game features a classical cover system where Harry can duck behind to regenerate his health. With him are his AI allies Hermione and Ron which fight on their own. New or upgraded spells are earned after level ups.
In addition to the shooter sections there are first-person stealth missions in which Harry needs to avoid detection. For this purpose he uses a invisibility cloak which has only limited power - if it runs out Harry is out in the open. It is recharged by standing still. Between the main missions the player has to solve other quests in any order. Those have nothing to with the movie plot.
The challenge mode is unconnected to the campaign and includes missions like killing as many foes as possible in a limited time.