This Means War!
It is a 21st century, and germans took over the world, and World War II layed in nazis' hands. You as a scientist; step into the time machine and go back into 1945 or couple of years earlier to find out what the hell has happened to world, how the nazis have won the war.
You'll encounter Hitler's SS troups and Wehrmacht infantry equiped with guns, machine-guns, bazookas, and similar weapons. But be careful if you run on some Commandos, 'cuz they know no mercy, and where they are, could be some Panzer tank in the neighboorhood. You'll also be seing planes up above, submarines, and other stuff you missed in "Wolfenstein 3-D", and some nice things like your tracks in a snow, mirror image on the floor if it's polished to darn well.
You can change resolutions quite to high, as well as some other things, speed, target-cursor look, and the game even supports 3D glasses (like the one that comes along with ASUS TNT/RIVA 2). Music and sound effects are rather amazing, and the whole dark atmosphere is great. Their speech, walking through the ruined cities, german castles, or diving... and as the game approaches near the end, you'll get into time machine again, and go 'back to the future', where you'll now find allied forces, and your-team scientists instead of german global domination. Unfortunately, you'll have to kill all of your men, as they will think you're one of nazis, or who knows what, but they sure won't be glad to see you. Oh, yeah, beware, as here are now rather power technology involved, with no old guns, unless you take some from the exhibits.