Start by running across both ladders, digging one hole in the third brick to the right of the right ladder, letting the guy fall in, then running across it to the right.
An alternate strategy takes advantage of the fact that if you are all the way on the bottom, the bad guys will run to the left, and if you are one level above the bottom they will run to the right. So, to start, dig down to your right. When you've grabbed the last gold, wait a little so the guys will run right. Jump onto the floor, run over to the ladder, and stop one level above the floor, The bad guys will run over to the right again. Now you can run up and clean out the top left.
When you're done with that, drop down to the level that the bad guys are on. Run up the first of the zigzag ladders in the left middle. Blow a hole in the rightmost block on that first platform. When the bad guys are starting to run up the ladder after you, drop down the hole and run over to the other ladder. You can move up and down the ladder there to keep the bad guys running back and forth so none of them drop into the hole you made. (You don't want to kill any of them, because you'll lose control of them if you do.)
Now you can clean out the top right. You'll drop through to the bottom when you're done. From there, move all the bad guys to the right, run up the ladder, blow your way into the bottom left corner, move the guys to the right again, and make your escape up the zigzag ladders in the middle.
Wait at the bottom until the last one drops from second-to-last rope. Then run up. One of them will have a piece of gold. To get it, dig holes on each of the first three layers on the way up, and grab the gold after the third one drops in. Then proceed with the rest of the level.
Either of the bottom corners is a safe spot where you can stay and all of them will gather in the bottom center section.
At the bottom right of the big middle section is a row of four bricks. It's useful to enter the middle section from the top right, run down, dig out this row of bricks, and stand to the right of it. When they've fallen in the holes, you can run up the ladder you're on, left across the ladders above them, and out the top.
One way to get the gold on the steps at the top left is to start by getting to the bottom left corner and luring them all to the left hand end of the center section. Run up the left-hand side to lure them all up there. At the top of that, run across the second ladder and dig a hole to drop into the middle section. Go down the ladder at the bottom of that and wait until they're almost upon you. Then run up and out the middle at the very top. They will head left again, and this will give you time to go down the steps at the top left and back down the ladder into the middle section before they've reached the top of the left section.
This is one of the trickier levels, with all sorts of ways to go wrong. But here's a procedure that will work every time.
The bad guys will henceforth be referred to as A, B, C and D, starting from the top left and moving right.
To start, drop down to the brick below you and wait. A will run into the hole on its left and be out of the game. B will drop into the hole to your left. (You'll pick up that piece of gold last.)
Now, run over and grab the gold in the top left corner. Wait there long enough to make sure that C follows you. Run down the long ladder next to you. (Again, wait and make sure that C follows you.) Drop through the hidden hole to the left; you'll drop to the bottom and grab the gold in the lower left corner. C will follow you to the top area.
Next, run up the ladder on your right and grab the gold to your right. Jump off to your right, and blow up the next block so you can get to the next ladder. Jump down; wait at the bottom of the ladder until C drops through the hidden hole into the bottom left area. Now C is out of the game too.
Once that has happened, go up the ladder and get the gold at the top of it. Next, blow up the block the gold was resting on, and the next four blocks below it. This will allow you to get the gold to your right. Get it. Then drop to your right, blow out the block to your right, and run to the next ladder. Run up this ladder, then run to your right and get the top right piece of gold (top of a ladder, between two blocks). Drop down off the ladder and blow out the block at your feet. Drop through the hole, move to your right, and get the gold at the lower right.
Now, drop down to your right and wait there. D will run up the ladder and do the circle thing. The block to your right is a hidden hole. When D is on the cable, drop into it and D will run to his left and drop down a hidden hole. While he's at it, you can run up the ladder.
If D has dropped the gold somewhere, collect it. If not, then wait at the top of the ladder and make a hole. D will drop into it and you can grab the gold and move on. (Be careful not to make the hole too early. If you kill D he can come back and kill you.) Once you have D's gold, move over to the left.
Now, it's time to spring B loose again. Run to your left and blow out the block to B's left. Run further to your left, past the cables. Blow out a block there and let B drop into it. Grab the gold, and the exit ladder will appear. Run up it and you're done!