People in the YouTube comments are saying this was meant to be played in co-op, and that's why the single player is unfairly hard and gives you more items than you have room for and items you don't have the stats to use and so on. That actually makes a lot of sense, since the opening cutscene introduced its cast like they were part of the Fellowship of the Ring, going off on an adventure together.
But, goddammit, if you're gonna make a game like that, just don't even give players the option of attempting it solo. Back in the days before every single game was required by law to be released on consoles and thus pass certification requirements like "must have a working single-player mode" they could have gotten away with that, but they probably figured they'd lose out on sales that way. Yeah, "sales" to people who will just return it when they realize it's unplayable.