First of all, do not give up!
To get the rifle scope do this: From the start of the level, do not go through the first opening you see. Instead, go around the nose of your ship and you will see a raised opening in the wall. Go through that and proceed till it ends. When it ends, go left and proceed through the opening that you see. At the end of it, you will see that open area full of Stormies and the security bunker. Kill the stormies and go to the bunker. Now, here’s the trick, you can shoot through the windows of the bunker, so first, shoot the oficer, then look across to the other side of the bunker and you will see a few reddish panels. Shoot the highest panel and viola, the door opens. Inside is the scope.
Then, do not go any farther, retrace your steps to where you went through the passage from the beginning and this time turn right instead of left, and you can see the entire compound as well as the door control you have to shoot (lower right of the compound) with the rifle scope. While you are there, go ahead and take out all the stormies and gun turrets. Lotta fun
If you wanna know the full walkthrough as well as where the secrets are, I might post them is anyone wants to know and if I have time.
Hope that helps.