Jurassic Park: Rampage Edition

On the Avirary level as Grant get the rocket laucher, then go to the Pterdacal nest and return to the bridge that has an item that looks like a cowboy hat. Before getting the hat-like item, select the rocket launcher. It will give you full ammo for the rocket launcher. This will work for any weapon except for the tranqulizer darts because you always have full ammo for that.

At the Aviary, with the Raptor, get to the top of the level. Reach the ptranadon nest, and move down until you reach a multi-health, then move back up to the nest. Move to the right of the nest until you reach the limb of the tree that moves down. Jump up three times while you are directly below it. Move left, kill the army guy and ove left as far as you can. Jump, and you will be rewarded with a life. Repeat until you have enough lives to finish the game. Warning your game will screw up if you have ten lives.