You need to jump the ledges to get to the entrance to the ship. You can make each of these jumps without the use of grenades, but you need to do some precise positioning to make those jumps. You can use a few bullets from the MOW-DWN to help you if you have problems. If you fail, you'll have to face two Devlins to get back to the ledges. The key is to locate the closest points between your starting and ending platform, so you want to jump off where there is a point, and land on a point at the other side. Also, it may be psychological, but if you are a mouser, looking up while jumping seems to carry you a greater distance.
Most of the level is straight forward, based on the terms. Make sure you use the 1x recharger down the stairs often.
Several points in the level allow you to move forward without killing all the monsters (and getting you to a point where those monsters are no longer a problem). Remember this, and you can save yourself ammo from its use with pointless kills.
There is a bank of eight or so switches that you have to hit in a certain order to succeed. Though trial & error will eventually get you the sequence you need, the simplist way is to flip all the switches on, then flip the 3rd switch from the left. This will open the way to the basement, where you'll have to watch for Devlins.
In this basement, there are several long platforms, with Devlins gaurding them. If you try to rush them, you'll most likely get caught by the Devlins before you can safely make it off, or you'll get crushed. The best solution to past these is to take one or two steps onto the platform, then back off, letting the platform rise. The Devlin will be crushed, and the platform will fall back into place - BEFORE it completely sets down, run forward, and you'll be able to make it across without retriggering the platform.
There will be one point near the second half of the level where you enter a room, and several bobs teleport in to take out Troopers. Let them do the work, and once it sounds like it has died down, take up the fight yourself. This is best done by using the door as a sheild, opening it up while you take several quick shots at the Hunters, then hiding as their shots fly by or hit the closing door. There are two 'turrets' that will continue to fire at you, so watch out for those.
After the room where Bob teleport in and the fusion turrets that shoot at you (and there's a save term in this room), there's a room with a square column in the center. The column is hollow and contains additional ammo.
When you enter the room that has the opening into the basement level, there is a save term and recharger in the far back right of this room (from the entrance). A window sits between them. If you look closely at the window patterns, you'll notice a difference, and you'll find a secret cache of fusion ammo.
After this room above, there's a section of hallway half open to the sky. One of the wall panels is darker than the others, and opens to a room with a secret terminal.