This is a realistic, first-person shooter world war II game.
The storyline makes heavy references to the previous two games and features multiple flashbacks, so I recommend getting and playing Brothers in Arms Road to Hill 30 and Brothers in Arms Earned in Blood before playing this game. The storyline in this game is compelling, but is slightly darker than in the previous two. Baker is having internal problems and wondering whether his past decisions were the right ones.
While the first two games take place during the Normandy campaign (Operation Overlord), this game takes place during Operation Market Garden- British General Bernard Montgomery's (aka "Monty") failed plan to liberate Holland, march through to Germany and "have our boys home in time for Christmas".
The gameplay of this game is very similar to the other two. Like the first two games, in Hell's Highway you command your squad and use cover and flanking to attack the enemy. However Hell's Highway has added a new element: destructible cover. Now you will only be able to take cover behind a barrel or something like that for a little while, before bullets start ripping through it. However there still is some cover (like walls) that doesn't break. This destructible cover adds a nice touch of realism to the game, but can make it a bit harder.
All in all, this is a good game, especially for fans of world war II games.