D — This is the first letter in the name and also the hardest to find. It is hidden in a secret level which also has many power up's. Go to the Eastern Mountain Range, in the southeastern part of the mountain you should find a Secret Level. This level should look like the catacombs that link the raptor pen to the visitor's center. Go down the corridor adn turn to the right. You will find an aisle filled with weapon power-ups. Pick these items up and make another right into a corridor with indented walls on your left. Go up to this indentation and the walls open revealing the letter D. Also in this room is an one-up. You can keep on going in and out of the Secret Level to aquire an infinite arsenal and infinite lives.
R — The R is found in the southwestern edge of the East Forest. Go to east end of the East Aqueduct and then head southeast to find the R.
H — Go to the top of the Visitor's Center and in the center you'll find the H.
O — Walk through Gate 2 and head northeast. Pass an exterior motion sensor, keep going north to the end of the path, the head east.
R — Directly south of the Nublar Utility Shed to find the second R.
N — When you've accessed the computer in Nedry's office, and can open the park's gates, go to the North Utility Shed. Go around to the northeast corner of the shed and go up the river. When you've went as far as you can you'll find the N.
E — At the Beach Utility Shed go southwest to find the E. Watch because after you've found the E the T-Rex will come after you from the west so be quick.
R — The last R is east of the Helipad. Go straigt east from the H on the Helipad until you find a Secret Path in the plants. When you're through, head north and you've completed the puzzle.
Go to the big rock formation (a wedge of rocks where one is above and the other is to the left.) Search the far right corner until you find a hidden cave. Inside you'll find a cache of extra lives. Come back here whenever you're low of life.
In the mountains, before the boat, pass the boulder and the raptor that comes out right whne you reach i. Go down two rock staircases, then go right. Then, when you reach the first left-hand corner, go in front of the wall, and pass through to reach a secret room. It contains power-ups and an extra life.
Pause the game and press Up (x3), Down (x10). L cycles weapons in one direction while R the other.
To get unlimited continues simply press L, L, L, R, R, R, L, L, R, R, L, R, L, L, R, R, L, L, L, R, R, R at the mission selection screen.