You are beginning the level near the dying Hayes. After his death, Jimmy will run outside in anger. Two dinosaurs will attack him there, so take the spear and quickly run to save your comrade.
In order to get out of the square, approach the gate (Jimmy will stand near it) and open it together.
Now, go through the corridor located behind Jimmy and then between rocks' shrapnels (lying here after the last tyrannosaurus rex's visit).
Go down and prepare yourself for hard battle. Two dinos are waiting for you there. Run down and quickly get to the place separated by walls (orange arrow). Entry will be blocked with some boards, so hurry and destroy them fast. Being inside, throw spears to kill the monsters (spears' location is showed in the picture on the right [red arrow]).
After eliminating entire threat, move ahead and take the way, which is leading through the high grass.
Run across the small section of the road, walk through the wooden catwalk, jump down from the height and run into the small building (right screenshot), where you'll be safe. There will be the reptile walking in the surroundings, so watch out.
In order to move ahead, run to the building located on the other side (some fire inside it). Fire the spear up and stab it into the shrubbery to clear the way.
During walking down, run as fast as you can to the building situated on the left side (there'll be a parachute and crate, so take advantage of it). A few dinosaurs are 'patrolling' the surroundings, and some 'bats' are flying in the air too. Try not to attack them (only when they'll attack Jimmy) and quickly run to the other side of the slope, to fire.
From there, use lighted spear to get rid of lizards feeding near the aircraft. They're standing in the shrubbery, so fry them with ease. If any enemy will survive, finish him off with ammunition acquired recently.
Go down to the aircraft. Unfortunately, only one place is available, and Jimmy will take it. Again, you'll have to make it all alone. The plane will take off (end of the stage).