If you run out ammo but have enough Tequila Bomb for the "Precision Aim", aim at someone and shoot. This will create 20 to 30 more rounds for the handgun. Always try having a enough Tequila Bomb for "Precision Aim" in the event you run out of ammo.
To defeat Wong and Dapang under the Hard and Hard Boiled difficulty settings, as soon as the checkpoint occurs (DaPang jumps down to you), run straight ahead and shoot the bottom right of the dragon statue. Almost always the statue will fall, killing Dapang instantly. You now have to be quick at this stage, especially on the higher levels. Once DaPang is dead you will have a few seconds to pick up the two paper cranes which fell after you destroyed the statue. Now at least five or six men will appear and run directly at you. Evade them as best you can and make your way to the golden guns to the left of the statue podium. Trade in your weaker guns. You will now have 32 golden bullets. You will most likely have a shotgun. If you do not, grab one. Make your way to the far left or right. Take cover behind a pillar and wait for the remaining enemies to come after you. When they get within a few feet of you, press LEFT or RIGHT, Tequila time will start. Kill them with one shot. Usually there is one remaining enemy that shoots at you from a distance. Ignore him. If you kill him, more enemies will appear. By now you should have or almost have a barrage bomb. Run upstairs and pick up a health pack if needed. Once you reach the top, Wong will start shooting, so you must be quick. Turn on Precision Aim. It is far stronger now that you have golden guns. Wong is weak against Precision Aim. Make sure you hit his head for maximum damage. While he is stunned, grab the paper cranes to the far left and right. Wong recovers quickly. Use Precison Aim each time you get a paper crane. There are two more paper cranes on the chandeliers. Swing on them to get them, but only do so after successfully hitting Wong. Once you have hit Wong as much as you can with Precision Aim, he will still be alive, but have very little life. Turn on Tequila time and fire your golden guns. He should die in seconds. If you are skilled at tossing grenades, use them. However, they are slow and will leave you vulnerable.
During the first level, after the second checkpoint when you are walking in the door take a right. You will see a damaged door. Shoot it and walk through the corridors. You will end up at a secret theater that shows two previews of games, The Wheelman and Blacksite Area 51. There is also a golden pistol, a paper crane, and a shotgun in the theater.