First Level Hints
To get extra help for "Metal Slug 2" for the Wii, shoot the guy who hangs above you before the first battleship comes, and he will help you.
After killing the first few sword-wielding enemies on the first level, pass the little hut where there are a batch of small palm trees. Stand under the trees and shoot up; two hostages will fall out of the tree.
Second Level Hints
At the beginning of the second level, the mummy level, enter the pyramid and you will notice a man nearby who is mining. Stop and shoot him to take the gem from him.
Before you blow up the entrance on the second level, jump on the barrel, press forward and shoot. Do this twice while you are using the shot gun to receive two additional hostages.
Walk all the way to the right of the second level and you will see a dead guy that's holding his hands up. Stab him with your knife after you jump down. He will then hold up a gem. Grab the gem from him and run away quickly. Once you grab the gem, he will take out dynamite and blow himself up.
To get extra gems on the second level, shoot at the eyes located within the background. Halfway through the second level, jump from the wooden platform on your right to access to treasure chests that contain one 30,000-point gem and one 1,000 point gem.
Train Stage Hint
During the train stage, shoot the smoke that comes out of the train to give yourself three additional hostages.