Okay folks, if you find the above Patrick-posted solution to my puzzle (
Diversionary Tactics) a bit unhelpful (it's more of an outline than a full solution), here is the solution in its full gory details:
To solve the level, the main tasks are as follows:
1) have Stinky get the boulder on the green switch and collect the 3 rainbow coins in sight
2) have Stinky set up a shield by pushing steel blocks near the spike area onto the "turntable" (the thing made of conveyor belts in the corners and ice elsewhere), and then put himself in line of sight with UFO so it won't bother Loof as he works
3) Loof then retrieves the reflector from the other teleport room, and transfers the 3 wood blocks on his starting platform to the other teleport room. The teleport on the other room must be surrounded on each side with a block before you can push the reflector onto the teleport without it teleporting. Then Stinky stops diverting the UFO, allowing Loof to lure the UFO to fire at the reflector to clear the way to the last rainbow coin.
4) Loof now needs to build a bridge across the water on the other teleport room. The key to doing so is to fill the water tile at the south side of that room (the tile that used to be a collapsing floor tile). To do so Loof must enter the teleport from north, which means Stinky has to divert the UFO's attention again. Once Loof's on the other side there're enough room for him to move the remaining two wood blocks onto water.
5) Finally, for Loof to get across the turntable safely, he needs to push stuff onto the turntable to collide with the steel blocks on it, thereby getting rid of them. Remember that the reflector can also be used for that purpose; however...
6) If you want to collect the bonus coins at the upper left, you must keep the reflector (well, at least you should unless you want to torture yourself). Have Stinky use it on Loof's starting platform to yet again divert the UFOs attention while Loof gets the bonus coins.
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Before I give the steps to each part, an explanation on the two unusual key tricks to this level (probably it's their unusualness coupled with a lack of good hints that made this level harder than expected):
a) "diverting the UFO's attention". The level was basically named after this trick, and a hint (in retrospect not a very good one) was included on this. The idea came out of a question I answered myself via playing with the editor some while ago: "if both Loof and Stinky are lined up with the same UFO, but in different directions, what happens?" Does the UFO fire at them both at the same time, or what?
As it turns out, the UFO always choose to fire at Stinky and only Stinky in such a case (maybe it can, um, smell him more easily? Sorry bad joke.

) Loof is ignored as long as Stinky remains at line of fire.
The level requires you to use this trick in a couple of places in order for Loof to safely and successfully complete his part, as well as getting the bonus coins at the upper left.
b) getting the reflector right on the teleport without it teleporting. Anyone who's played Wonderland's "Trapped at the Teleporter" and "Confounding Teleporters" should have a basic understanding of how to "manipulate" a teleport. The way the teleport works is, when something enters it, it tries to exit moving in the same direction. But if that won't work because the exit is blocked, it will try a bunch of other directions. If every direction is blocked then the thing will stay at the teleport it enters, without teleporting to the other side.
If it's Stinky you want to put onto the teleport without teleporting, you usually need to put two blocks on each open side of the teleport; one block is not enough because Stinky can push the block along as he exits out of the teleport. However, for a block-like object like a reflector, one block on each open side is enough, for the same reason that Stinky can't push two blocks at once.
I probably should've include a hint within the level about this.
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Solutions to individual parts:
1) Stinky must first move one step to the right onto the conveyor belt tile. He must leave that rainbow coin nearby untouched. He then pushes the boulder down, which will be stopped by the uncollected rainbow coin. Now he must collect the rainbow coins and bonus coins on the green button, in order to clear way for the boulder. Finally, push the boulder to the right, collecting any remaining rainbow coin in this room, and push the boulder down to the green button.
The only twist here is that when moving across the UFO's line of sight (which will happen a number of times as you work this part out), Stinky must go through that tile with a sign post in order to survive. Any closer and the fireball will get Stinky.
2) In this part, Stinky needs to push both steel boxes onto the "turntable", which is that 3x3 contraption made of conveyor belts at the corner and ice. The basic moves to do so are as follows: wait until the spikes just gone down, then push the steel box to the right until it's on the spike tile. Then go around the long way to the right side of the steel box, and push it left once so it's back on the left side of the ice. Go around the long way again and push the block all the way down until it goes into the turntable. Repeat for the other steel box.
The spikes are slow enough that, as long as you make sure you don't push the steel box onto the spike tile until you see the spikes just gone down, you should have a reasonable amount of time to do the above. Remember too you can move faster if you slide across an ice tile instead of going around it. And by the way, that lone wall tile in this room (the one sandwiched between the two ice tiles) is actually a fake wall with a bonus coin inside!
If you want to get all the bonus coins later though, you want to be a little more careful. Both steel boxes rest on top of collapsing bridges that can only be walked thru twice. To get the bonus coins you need to make sure you don't go across each bridge more than once at this point. To do so, the trick is to first push the lower box one step to the right, off the collapsing bridge, but
do not follow through (ie. don't push it onto the spike tile!). Instead, move left to get off the lower collapsing bridge, then proceed to push the upper box to the right until it ends up on the spike tile (time it of course). Then while you are en route going around the long way to the other side of the steel box on the spike tile, push the lower box down onto the turtable.
You need both steel boxes revolving around on the turntable. When pushing the second steel box onto the turntable, make sure you time you push so it doesn't smash into the first steel box!
Phew! Once this is all down, move Stinky against the right edge of this room [be careful with the spikes] and go all the way down until he lines up with the UFO. Now the UFO will fire continuously at Stinky, but the rotating steel boxes will block the fire. Voila! Stinky can now divert the UFO's attention away from Loof for as long as you need.
3) Now Loof needs to retrieve the reflector from the other room, and transfer the wood blocks to the other room. To make things more clear, I'll refer to the teleport on the left as "teleport L" and the one on the right as "teleport R".
To do so, first push the wood block at teleport L's north one step to the right. Next, enter teleport L going right. Then proceed to push the reflector one step to the left and then up into teleport R, so it emerges at teleport L's platform. Before Loof heads back to his starting room though, make sure to move the steel box so it's on teleport R's left side. (You'll need to move through the collapsing bridge on the left to do this.)
Now Loof heads back to his starting room by entering teleport R going left. Then proceed to just push each wood box into teleport L. When you're finished, teleport R should be surrounded by 3 wood boxes and 1 steel box, which allows you to move the reflector right onto teleport L without it teleporting.
Now Stinky stops diverting the UFO, so Loof can get the UFO to fire at the reflector to clear the way to the last rainbow coin. Woo-hoo!
4) Loof now needs to build a bridge across the 2 tiles of water at teleport R's room. To do so, have Stinky resume diverting the UFO's attention. Then have Loof enter teleport L from above. He will emerge from teleport R going down. Now he can build a bridge across the water by first using the wood block on the right, then push the steel box up all the way against the wall, push the remaining wood block located above teleport R one step to the right, and then go around and push that onto water as well.
5) Now for Loof to exit safely, you want to get rid of the steel boxes at the turntable. To do so, first make sure Stinky is no longer in the UFO's line of sight! Then have Loof push the steel box (the one originally in the teleport R room) onto the turntable. It should collide with one of the steel boxes, getting rid of it.
Now one steel box remains at the turntable. You can get rid of it by retrieving the reflector at teleport L's room and push it onto the turtable, timing it so it smashes into the remaining steel box. (Be careful when you retrieve the reflector! Remember Stinky can no longer divert the UFO's attention now that you broke the turntable shield! In particular, make sure you enter and exit teleport L and R horizontally, and you must make sure to push the reflector into teleport L moving either right or left.)
If you want to collect the bonus coins however, you need the reflector, so one steel box will remain at the turntable. You can still get across the turntable, but you'll have to time your moves carefully to do so.
6) To collect the bonus coins at the upper left, first make sure in part 3 you only stepped on each collapsing bridge near the spike room once. Now, have Loof move across one of the bridges into Stinky's starting room and wait. Then have Stinky enter teleport R from either the right or the left. Then place Stinky to the south of the reflector. The UFO will again fire madly at Stinky, this time protected by the reflector. Loof can then get the bonus coins, go across the remaining collapsing bridge, and exit the level.
Now have Stinky go into teleport L, again only horizontally, and exit.
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As a final comment, I want to mention that originally, I have a much trickier solution in mind for getting the bonus coins, involving having only one steel box at the turntable when Loof is working to retrieve the reflector. This will only give Stinky at best a 2-second protection, which means Loof can only take about 2 or 3 steps before you need to move Stinky away from the fire.

As it turns out though this devious and almost impossible solution is unnecessary for getting all the bonus coins. (Phew!)
Thanks again for playing and sorry for all the frustration it might've caused!