Unlimited ammunition
Simply press Left(3x's), Right, Left, Right, Y(2x's) when your at the main menu.

Level select
Hold LB + RB then press Left(2x's), Right(2x's), Y(2x's) when your at the mission selection screen.

Achievements
Finish the achievements listed below to access the listed number of Xbox Live Gamerscore points (1,000 total possible points).

Completed Training (50 points): Complete Basic Training.

Veteran of the Winter War (60 points): Complete The Winter War on Veteran difficulty.

Veteran of Stalingrad '42 (60 points): Complete Not One Step Backwards mission on Veteran difficulty.

Veteran of Fortress Stalingrad (60 points): Complete Fortress Stalingrad mission on Veteran difficulty.

Veteran of El Alamein (60 points): Complete The Battle of El Alamein mission on Veteran difficulty.

Veteran of The Tank Squadrons (60 points): Complete The Tank Squadrons mission on Veteran difficulty.

Veteran of Rommel's Last Stand (60 points): Complete Rommel's Last Stand mission on Veteran difficulty.

Veteran of The Battle for Caen (60 points): Complete The Battle for Caen mission on Veteran difficulty.

Veteran of D-Day (60 points): Complete D-Day mission on Veteran difficulty.

Veteran of Hill 400 (60 points): Complete Hill 400 mission on Veteran difficulty.

Veteran of Crossing the Rhine (60 points): Complete Crossing the Rhine mission on Veteran difficulty.

Won the War (150 points): Complete the Single Player Campaign.

War Hardened (200 points): Complete the Single Player Campaign on Hardened or Veteran difficulty setting.

Hints & Tips

Veteran mode

Veteran mode will cut life expectancy to three or four shots until you die. But Veteran mode does not improve the enemy's aim or strategy. Just use small blocks or bulges of hills as cover and crawl. Because you do not get points for kills, do not take the Nazis head on. Let your allies lay fire, if there are any. If not, throw a smoke grenade and shift between crouch and crawl positions, laying cover fire and stall some time for the smoke grenade to spread before the Nazis come. Now use this smoke cover to fall back to the closest safe position where you can regroup or hide and pick the Nazis off from a distance.

When your playing on the Veteran difficulty in campaign mode, always take cover. When you reload or get hurt badly go prone or get behind a wall. Also, use your smoke grenades. You will need them to get past certain parts of the game.

Suggested weapons

1.Whenever you have the chance, pick up a Kak 98. It is one of the most powerful guns in the game. There is a scoped-Kak 98 in the last level (Dragon's Teeth) in the 2 bunker in the building. 
2. The most common bolt-action rifle is one of the best weapons for small groups of enemies. It may be a bolt-action, but it is a one-hit kill almost all the time. Make sure to keep an automatic for the slow reload. 
3. Smoke grenades provide instant concealment. They are very useful for getting close to tanks on the Russian front.
4.SMGs work best at close range. The PPSH 42 is recommended.
5.Rifles are useful at short to medium range. The best ones are the SVT40 and Gheher because they are semiautomatic.
6.Sniper rifles are very useful for picking off machine gunners before they can get set up. The Gheher sniper rifle is recommended because it is semiautomatic.