I'll preface my review by saying Young Justice: Legacy has a lot of potential and is probably a decent game on consoles - it just wasn't ported very well to PC.
Me and a friend - both fans of the Young Justice cartoon - purchased the game to play online together. Before even playing the single player campaign, we attempted to play together. I was able to host a game, but I was stuck on the "waiting for players" screen indefinitely. My friend could not even host OR join a game, he simply received vague error messages.
With multiplayer not working, we decided to play the single player campaign separately. I immediately noticed that the game's menus did not have support for a mouse cursor, you must use the arrow keys. Additionally, the "space bar" had been chosen as the primary "make a selection" key, not the standard "enter key" or mouse click. These were minor inconveniences, but probably a red flag.
In the game, I was immediately annoyed by the fact that the camera could not be adjusted. In narrow pathways (which this game has many of) the camera really impedes gameplay. I ignored this and continued on.
The combat was pretty typical of a hack-and-slash. Mindless, but enjoyable. Unfortunately, the voice emotes were very repetitive and triggered way too often. My biggest issue with the combat was the enemies' aggro radius. It was very small, and moving out of this radius caused the enemies to reset and go back to their patrol locations. I found myself accidentally exploiting this as I was playing. I would attempt to back off a little bit to do some ranged attacks and the enemies would reset, giving me time to regain health. It was very unnatural.
I continued. I found my first chest, which I had hoped would contain some interesting item - but it was empty. My friend found the same chest, no item.
I ran into another game-breaking bug. I have two monitors, and my cursor was not limited to the game screen. As I encountered larger battles, I found myself clicking outside of the game and minimizing my session.
At this point, I exited the main game and decided to take a look at the mini-games in the central hub; particularly, the trivia game. The game seemed interesting, especially for fans of the game, but every time I finished I assumed the game froze because I could not return to the hub. The UI prompted me to press "space bar" to exit, but this did nothing. Eventually, I discovered that you actually had to press "s" to exit. One of the many control-based typos in the game.
Overall, the combat was pretty polished and fun. Fans of the Young Justice cartoon would appreciate the story. The graphics were very out-dated (I've seen comparisons to the Gamecube, which are pretty accurate) but they weren't unreasonably bad.
Unfortunately, though: the menus were frustrating to deal with; the controls were unintuitive and typos worked against you; and the game wasn't interesting enough to justify the gameplay bugs (empty containers, bad AI).