This is not only a recreation of the Normandy landing, but also a recreation of the Unreal Tournament '99 level. Though most of it is reasonably faithful to the original level, the beach section has been greatly expanded to look more like the beach at Normandy to great effect. Rather than the single boat, barbed wire fences and so on, the beach now goes on for miles, and the sea is swimming with boats. The only thing I'd change is that the long-range cannon is the ion cannon from Robot Factory, rather than something more authentic looking.
The attackers first objective is to pick up some bangalores partway across the beach and take them to the wooden barracade in order to destroy it. As the attackers get no less than six chaingun turrets, and sniper rifles, a team of accurate marksmen should be able to hold off the attackers for a good while. Once the barriage is destroyed, the attacking team must proceed around the two towers (the right-hand path is shorter) to the entrance to the bunker and enter it (while avoiding the defending team, obviously).
Once inside, the attackers must proceed through the boiler room, in which the defenders have two more chaingun turrets, to a switch to open the doors to the armoury. The doors, once the switch has been pulled, ironically take a while to open, which allows the defending team to get into position.
The attackers must then proceed up another set of corridors to another objective point, then from there mount their attack on the main cavern. There are two ways to complete the mission - either by destroying the cannon itself (which takes a lot of damage), or take the overhead walkway around to the control room where one shot will destroy the control circuits and overload the cannon. If you're on the defending team, keeping the opposing team away from the control room is, of course, vitally important.
This level is almost as good as any of the levels which came with UT2004, and (along with the Battle of Celeste) is one of only two third-party Assault maps so far to make it into my map rotation.