Use Cover
Drake needs to be quick on his feet and on the draw in order to survive his adventure. Use any available cover to extend Drake's health bar. As Drake takes damage, the screen gradually fades and turns black and white. Duck behind cover by pressing the "Circle" button when Drake is near a large object, such as a crate or a wall. This will protect him from most of the enemy fire. If you wait long enough, Drake's health automatically regenerates.
Use Your Rewards
As you play through the game, you earn medal points for completing certain tasks. For example, you can earn a medal that's worth 10 medal points for killing 20 enemies with the Desert-5 gun. If you earn 300 medal points, you can unlock the unlimited ammo reward, which will help you defeat enemies and stay alive. If you turn on the infinite ammo reward in the rewards menu and select a strong gun, such as the Desert-5 (it kills most enemies with one bullet), you can defeat enemies quickly and efficiently without too much regard for Drake's health.
Study Each Level
Knowledge can be a deadly weapon in "Drake's Fortune," especially if you know the level layout, the enemy locations and the number of enemies you will face in any given area. If you find yourself stuck on a level and feel that you need unlimited health to get through it, pause for a second and study the layout of the level. Look for toppled stone blocks or crates to use as cover and note where the enemies come from. For example, in the first stage, Drake gets attacked while he's on his boat. The enemies climb over the edge of the boat at specific locations. If you memorize the locations and learn to anticipate where the enemies will be, you can take cover as necessary, extend Drake's health and make it through the stage.
Reduce the Difficulty
"Drake's Fortune" has several difficulty levels to suit your experience level. If you find yourself stuck, restart the game on an easier difficulty level. The difficulty does not change the basic layout of the game -- you'll still run into the same enemies and must complete the same challenges to succeed. By restarting on an easier difficulty, you can learn the layouts of each level and discover the best weapons to use and the best places to hide. As you progress through the game, gradually increase the difficulty and keep practicing.