I've split it up into sections to which you can jump if you want to:
When you've come out of the closet, walk left and you'll enter the library. If while walking around you get told that you hear footsteps, quickly go through a door or go off the edge of the screen because if you don't you'll be caught and shot. Go out through the door to the left and left down the corridor to find the dead crew member. Search him and take his keycard . Go back to the library... an old man should stumble in through the right hand door and fall to the floor. Look at the man and he should talk to you, telling you that people are stealing the Star Generator and says "astral body" . Go to the cartridge retrieval unit and enter "astral body" (sans quotes). Take the cartridge , but don't try to insert it in the computer or you'll be killed.
Now you have to escape the Arcada before it explodes. Go left and then down the elevator then right. You can have a look in the Star Generator room on the way (the broken door) and look at the monitor at the north wall which will tell you how long you have before the ship destructs (from the start of the game till boom time is about 20 minutes). Take the down elevator, then head to the right. Look at the console in front of the shuttle bay window and press the open button . Go right and slide the keycard through the slot  then enter the elevator.
Press the left button on the wall at the back and take the gadget from the closet  and turn it on. Press the right button and get the suit . Go to the console at the bottom and press the airlock button. Leave through the airlock to the left. Push the platform button on the console  and enter the pod. Wear your seat belt. Push the power button. Close the door. Pull the throttle and you'll launch, escaping the Arcada . Press the autonav button  and in a short while the system will find a planet on which to land.
Carry on around the path until you reach a broken arch... walk into the archway  and you'll be transported underground. Get the small rock at the right of the cave then go to the left. Walk along the back wall to get past the grate without being eaten and then put the rock on the geyser . Leave through the door which has opened at the back and leave through the back of the next cave as well. Put the glass in the beam  and take the path up the back.
In the next cave, dodge the drops coming from the ceiling  and carry on to the right. Make sure your dialect translator (gadget) is switched on before walking right again. You'll be told to kill Orat and returned to the surface.
Make your way down the path and then off the back of the screen and then into the cave opening on the right. Throw the dehydrated water at Orat  and pick up the piece of him that's remaining . (You can also kill Orat by leading the spider into his cave and letting it kill him if you don't kill the spider earlier.) Make your way back up to the arch on top of the ridge and back to the alien's chamber. When told to, drop the Orat part  and walk forward.
The people will give you a skimmer, but first put the cartridge into the console at the back of the room . Take the cartridge  and enter the skimmer. Turn the key and you'll be taken to the surface... dodge the rocks and you're on your way to Ulence Flats .
Now we need some more money, so go to the slot machine. Play until you break the bank and make B$250. Someone will offer to sell you something if you go behind the bar; don't go. Go left to Tiny's Used Spacecraft. Don't buy the ships on that screen; go to the back and buy the only ship on the screen behind . As Tiny said, you'll need a droid to fly the ship so go right to Droids B Us. Buy the droid on the right at the back  and then head back to the ship that you bought. Enter the ship and push the load button to load the droid. Tell him to head for sector HH and soon you'll be in view of the Deltaur .
Open the chest and put your jetpack inside it. Push the chest so that it's underneath the grate then stand on the chest and open the grate. Enter the grate  an crawl to the left. Climb the ladder and then into the tunnel to the right. Kick the grate at the end and then open it and exit into the laundry room . (This can also be done by climbing inside the chest  and waiting until someone picks you up and drops you off in the laundry room.)This is where you can get extra points. If you want to get up to to 160 points instead of 157, open the chest and put your jetpack inside as usual. Then enter the grate  and get out. Open the chest and hide inside it . After it is carried to the laundry room, get on top of it again and open and enter that grate , then get out of the grate back into the laundry room . You've gained 3 points! (You should have 3 points more than all the scores inside  from now on.) Open the washing machine and enter it  then exit when you've been washed up. Now you're in a Sarien uniform, with a Sarien ID in the pocket (look at the uniform to put the ID in your inventory). Leave to the right and talk to the guard who appears . Keep talking to him until he asks if you have played King's Quest 2 (You might have to talk quite a number of times.) Say "yes" . Try to kiss him . Enter the left elevator and head left when you get out. Take the elevator to the upper level and head right until you reach the armoury. Show your ID to the droid and when he goes to get your gun, steal a grenade from the counter . The droid will give you your gun  then head left.
Drop the grenade on the guard . Go and show your ID to the droid in the armoury again and get another grenade when it leaves . There's nothing you can do with it, so drop it in the same place you dropped the first one if you want to get it out of your inventory (or just hold on to it, if you prefer).
Head back to the lift on the left. When you get to that screen you'll trip and lose your helmet. After losing your helmet you'll be attacked if caught, so if you see a guard shoot him . Be sure to encounter and shoot at least one guard for the points. You can't shoot droids, you have to avoid them (walk off screen and then return, be sure to be wary when walking offscreen to shoot any guard on the screen you walk off to).
Go the the Star Generator room. Search the body and you'll find a remote control . Press the button  to deactivate the shield around the Generator. Look at the console and enter the destruct code (6858) . Head back to the lift, enter it and then enter the right hand lift . Enter the shuttle and press launch [202/202] (or [205/202] if you took the extra points).
Congratulations! The Deltaur explodes and you save everyone! You either have full points or MORE than full points!