Generally speaking the game doesn't hide its simplicity. You might have a decent enough reservoir of spells to tap into from the weapon wheel menu, but you can easily finish the game using Stupefy, the first spell the game grants you. Some enemies require a bit more variation with your spells: the fairies, for example, can only really be dealt with by throwing a potion at them that slows their speed, allowing you to take them out one-by-one using any basic spell.
And here's another bone the game throws you: the four-points system. This is a re-castable cookie crumb trail that functions as a very temporary roadway sign, directing you down the right path within each supremely linear environment. You might be asked to explore a house where most doors and exits are locked, leaving little to really explore at all. But regardless, Four Points can be a damn good system - if only because you can control it. Where some games would use a cookie crumb feature as a stand-in nanny to grip your hand like a vice and drag you to your next objective, Four Points only points you in the right way when you bother to cast it, and it only directs you down that route briefly before the glowing line disappears.
But there are bigger issues elsewhere. Deathly Hallows is, in theory, a game of two modes - allowing you to either stealth your way through areas without fighting, or to focus completely on combat, depending on your play style. I say "in theory” because Deathly Hallows doesn't seem to use stealth as a different way of reaching objectives - just as an alternate way of getting to inevitable combat. You might stealth toward the middle of a camp of enemies to save a locked-up Muggle, but there are no prizes for guessing what happens once you've unveiled yourself, rendering your previous stealthing pointless.
Considering most missions work identically – run through an area and have intermittent fights along a linear path until you reach your objective – it's tedious that you're unable to deal with these quests in different ways, and the stealth system is successful only in the sense that it hints at a more complex and interesting game.
Combat has a similar issue. On the one hand it's a clever mash-up of traditional shooter tropes. The AI might not be particularly clever, but cover degrades over time - meaning you inevitably have to move from area to area if you want to survive against big groups. On the other hand, and this is important, it's almost impossibly buggy. Harry regularly slides across the room, in and out of combat, whether you've got a hand on your controller or not. Ron and Hermione will often shoot at walls and non-existent enemies, while genuine foes will merge into walls.
The game is full of good ideas tethered to a slop of bugs, but more significantly it's never much of anything. It's never varied enough to have interesting combat; it's never open enough to let you explore; it's linear but never driven enough by its narrative to be an enthralling, story-driven title. It's a impressively dark film tie-in, and an ambitious one at that, but don't expect anything more.