Lemmings/Tricky Levels 11-15

Level 11: Lemmings in the Attic

 * 8 minutes, release rate 20, save 84% of 50 lemmings

Set the first few lemmings building to seal the gap to the left without losing any (it shouldn't need more than three). Then when the lemmings are heading to the right again, have one start building a ramp on the second tile from the left, anywhere between the left edge and the middle (this will be the ramp to the exit); and have another one build a second ramp about two tiles' width to the right of the first (to protect any lemming falling from the first ramp from falling too far and splattering). Make sure that the second ramp stays ahead of the first, until it meets the wall and there's no longer any danger of falling from it. Keeping both ramps going is probably easiest in versions of Lemmings which have the Visual Sound Effects option, so that you can see exactly which of the two builders is running out of bricks before he does so; otherwise you'll only get about a half-second warning (the shrug).

Once you have a ramp to the wall blocking off the exit (or just below that wall), bash through said wall (you may have to extend the exit ramp a little afterward) and then through the second blocking wall. You will get 100% saved with plenty of time and builders to spare.

Level 12: Bitter Lemming

 * 8 minutes, release rate 1, save 80% of 50 lemmings

At first, alternate between making the emerging lemmings floaters (otherwise they will splat) and building a zigzag ramp up the hole so as to reduce the fall to a safe one.

Once the latter goal is accomplished, turn one lemming into a climber (there is no danger of his climbing out of the left side of the hole; an overhang there will stop him). When he's almost past the gap in the brickwork, have him mine until he gets near the right hand side; make him build to turn him around, then mine to the left until he's above the left side of the platform below; turn him around again and have him mine through the bottom of the brickwork. From the right edge of the platform, build a ramp to the exit, then when it's nearly done build a ramp to let the other lemmings out of the entrance hole. Finally, increase the release rate to 99.

Level 13: Lemming Drops

 * 8 minutes, release rate 1, save 70% of 80 lemmings

Make the first lemming into a floater, then a builder the moment he lands on the stairs. Block both ends of the platform below the entrance.

Build a zigzag set of ramps until your scout is out of the hole and on the column that is the right wall thereof, then starting from the middle of that column, zigzag up to the short wooden platform. Drop to the long wooden platform below it, build a ramp to the exit from there, and release the right-hand blocker.

Level 14: MENACING!!
(This level isn't included in Lemmings For Windows, so I know nothing about it. Somebody else will have to fill in this section.)

Level 15: Ozone Friendly Lemmings

 * 5 minutes, release rate 50, save 60% of 10 lemmings

With the bomber skill selected and the cursor at the position of your choice, bomb four lemmings as they reach that position.