There are two other levels in which you can "warp" from the Medium path to the Hard path. They are "Catch the Orb" 
and "Power Down" -- (both found in the Medium path). In Catch the Orb, you'll have to chase down the third bounty 
hunter within the game (don't pick up the fake golden orb of matter) and once you destroy the hunter, he'll drop the 
real golden orb. Get it, and return to the starting point -- now you will be able to play the Hard path.

In Power Down, simply make your way to the end of the stage, (pick up a resnic reanimator -- extra life), hit all three 
switches, then destroy the enemies that come out of the now unlocked doors. Once this is done, the thing in the 
middle will lower it's protective armor, and then go to the front of it and blast the Red "eye".

(The other way to remain on the medium path, is to blast the eye at an angle while it's armor is still up.)

Extra Lives on the first Hard Level
First beat the fist level in under 1 minute 40 to access the hard levels. Next do the first hard level. Fly up and right down 
the hall. Bump the two or three guys out of the way and fly into the tunnel straight across the room. Get the one up and 
go back. Go down the tunnel straight down. Keep going towards the last green thing you have to protect. In the room right 
before the tunnel to last green thing is four square holes. Down one of the holes is a second free man and some sheilds 
and some weapon energy. Simply stay there till it says mission failed and you will be one man richer.

Fast Titan
To make a Titan go fast, go forward a little, then brake and quickly shoot the Titan. Itll go so fast your enemy wont be 
able to move out of the way.

Freeze Enemies
On the "Press Start" screen enter the code R, Z, Right, Right, C-Up, C-Left, C-Right, C-Down.

Gore Mode
At the "Press Start" screen, press Z, Down, C-Up, C-Left, C-Left, C-Left, C-Left, C-Down.

Infinite Primary Weapons
At the PRESS START screen press A, R, Z, Right, C-UP, C-RIGHT, C-DOWN, C-DOWN.

Infinite Secondary Weapons
At the "Press Start" screen, enter the code B, B, Z, Left, Left, C-Up, C-Left, C-Right.

Infinite Solaris
At the "Press Start" screen press B, L, L, Z, Up, Down, C-Up, C-Up.

Infinite Titans
At the "Press Start" screen, enter the code A, B, L, Up, Up, C-Up, C-Up, C-Right.

Invincibility
At the "Press Start" screen enter: A, Z, Z, UP, LEFT, C-LEFT, C-LEFT, C-DOWN. You should get a message saying 
"INVINCIBLE". 

Level Select and Battle Mode
On the PRESS START screen press A, R, Z, Up, Up, C-Up, C-Down, C-Down. The screen should say MISSIONS OPEN 
and you will now be able to access all levels plus Battle Mode.

One-Shot Kills
With this code, conserving your ammo is easier than breathing! Press B, B, B, L, R, Left, Down, Down on the "Press Start" 
screen to make your enemies very, very, very vulnerable to any attack.

Psychadelic Mode
If you have any paper bags, you might wish to have them handy when you use this code! To make the background colors 
flow constantly, press A, R, left, right, down, top C, C-left, and C-down on the Press start screen.

***This code is not good for people with weak stomachs or tendency to get migranes!!!

Skip Credits
To skip the credits, reset the Nintendo 64 after the opening credits start.

Stealth Mode
At the PRESS START screen press UP, UP, UP, UP, RIGHT, DOWN, C-LEFT, C-LEFT.

Unlimited Energy
At the "Press Start" screen, press L, Z, Left, Right, Down, Down, C-Down, C-Down.

Unlimited Nitro
At the PRESS START screen push  B, B, R, UP, LEFT, DOWN, C-UP, C-LEFT. After this, during the game you will have 
infinite, nitro, just hold B And A to use it. 

Wireframe Mode
At the "Press Start" screen, press L, L, R, Z, Left, Right, C-Up, C-Right.