Gnome Locations:

This part is completely copied from a fellow Gamefaqer

Thanks for the locations "Yars Revenge

Apparently the previously posted information from the strategy guide is incorrect. Levels 1, 7 and 8 each have one gnome, and levels 2-6 have two gnomes. Here is a comprehensive list I just posted to the codes section (might want to keep this bumped until it's accepted):

Tip The Idol: The gnome in Level 1 -- Hop over the fence in the hallway just before the turret/elevator and TK the gnome to you (it can be seen through a floor vent).

TK Alley: First gnome in Level 2 -- TK surf into the second story of the cryo lab once the countdown begins. The gnome is behind the wall where Leonov stood (once you pick it up, there's a pair of skinny doors at the end of the hall on the left. take the one on the right to find a secret passage back to the room by elevator).

Bouncy, Bouncy: Second gnome in Level 2 -- It's in a niche between the two static filled jumbotrons at the very end of the level. Walk up the broken floor that forms a slant and TK the gnome to you.

Gearshift: First gnome in Level 3 -- It's on the roof of the shipyard entrance near the guard post where you obtain MC. Stack up boxes to reach the roof of the building left of the sliding ladder & sniper, then TK the gnome to you.

Panic Room: Second gnome in Level 3 -- Inside the shipyard there's a hidden area enclosed by the large shipping crates. Climb up the guard tower with the crane lift and you'll see it below on the left.

Bottomless Pit: First gnome in level 4 -- After destroying the four "chompers" in the room with the dock worker cut scene, the gnome is inside a secret passage connecting the pair on the right.

Up & Over: Second gnome in level 4 -- In the conveyor belt room, there is a pair of ladders in the far right corner. The one on the left is blocked by a fence. Turn off the chompers & flame jets then hop onto the conveyor. Jump off near the stairwell in the middle and you will scale over the fence. Climb up the ladder to find the gnome on top of a pipe.

Floor of Death: First gnome in level 5 -- There are two destructible gratings in the marble atrium; one at the start of the illusion offices, the other in the hallway leading to the illusion chamber. Blast either open; they form a connecting ventilation shaft which leads to the gnome (can be seen from behind the vent in the illusion chamber control room).

Survival: Second gnome in level 5 -- Start walking forward when the graveyard battle begins. You'll see the gnome behind a tree in the far corner (near a medical kit).

Gasoline: First gnome in level 6 -- After the fusion reactor is deactivated, walk through the door and climb down the ladder to find the gnome in the pool.

Psi Pool: Second gnome in level 6 -- Destroy the triple turrets to the right of the entrance to Marlena's chamber. The gnome is in the back left corner of the adjacent computer room.

Stoplights: The gnome in level 7 -- Kill the four snipers at the beginning of this mission (tip: beat the level and replay it on easy). Set up a staircase of boxes and climb onto the pillars behind the spawn. The gnome is on the facade's third story left (search with your sniper scope then TK it to you)

Aura Pool: The gnome in level 8 -- It's behind a boulder just before you enter the alien gateway (long green & black catwalk before the elevator to the final battle).

Gnomotron: Find all gnomes -- Collect the thirteen main mission gnomes (and save your game each time).