I don't know if you look at editor maps before you play, but these hints are written from the perspective that you don't. (Then again, if you viewed editor maps, you probably wouldn't be asking for help on levels like Icedeath...) Also, you said "last 10", then listed 5 levels, then started from the 13th last level, so I just said screw it and wrote some advice for all 137-149.
Goldkey - take some time to chart the upper section, don't blindly take action as there are many ways to trap yourself. The goal isn't immediately clear, but if you find the fake wall you should see what's needed to reach the exit.
Partial Post - you don't need to do the blocks one at a time, but other than that massive timesaver there aren't really any solving tips.
Yorkhouse - run
Icedeath - you can either chart a path as you go by trial and error (writing down the correct path when you find it), or you can just open it in an editor / look at the AVI.
Underground - safe solution: try to open the dirt as much as possible. For example, clear all the starting dirt, then release a paramecia and let it go by, then open all the dirt surrounding where the paramecia was, etc. You should have a massive block of land pretty quickly and from there it gets pretty easy. Awesome solution: see yorkhouse
Pentagram - map / AVI / trial and error
Stripes? - you can look at a map, although the pattern should become quickly obvious. Just be patient.
Fireflies - patience, it's all too easy to get hasty and end up having to angrily close an "Ooops!" dialogue box.
Thanks to... - I heard if you manage to complete this level with no fire boots while simultaneously erasing all of the invalid ice/ice tiles, all the secrets of the world get revealed to you. Probably best to just beat this level normally.
Cake Walk - What Dave said for the most part. Block the fireballs with a block (you have tons extra). You can bridge over the ice to reach the left side if you want, which is a ton faster and uses less blocks.
Force Field - The left side of the level is easily completable, but there are only two ways to the right side. Make sure you know how to easily get back to these access points, as you will need to get them often. Also, don't watch the 970 AVI, it'll just make you depressed.
Mind Block - Build south to start, this will allow you to build back up. Once you get the middle section opened up a bit to where you can push the block in any of the 4 directions, it's just a matter of patience. Bonus insanity points for blowing up all the bombs, and super bonus insanity points if you fill all the empty spaces with blocks once you're done.
Special - Assuming you know how the level ends, just look at a map to see which blocks are hot. Failing that, just trial and error it I guess.
Goldkey - take some time to chart the upper section, don't blindly take action as there are many ways to trap yourself. The goal isn't immediately clear, but if you find the fake wall you should see what's needed to reach the exit.
Partial Post - you don't need to do the blocks one at a time, but other than that massive timesaver there aren't really any solving tips.
Yorkhouse - run
Icedeath - you can either chart a path as you go by trial and error (writing down the correct path when you find it), or you can just open it in an editor / look at the AVI.
Underground - safe solution: try to open the dirt as much as possible. For example, clear all the starting dirt, then release a paramecia and let it go by, then open all the dirt surrounding where the paramecia was, etc. You should have a massive block of land pretty quickly and from there it gets pretty easy. Awesome solution: see yorkhouse
Pentagram - map / AVI / trial and error
Stripes? - you can look at a map, although the pattern should become quickly obvious. Just be patient.
Fireflies - patience, it's all too easy to get hasty and end up having to angrily close an "Ooops!" dialogue box.
Thanks to... - I heard if you manage to complete this level with no fire boots while simultaneously erasing all of the invalid ice/ice tiles, all the secrets of the world get revealed to you. Probably best to just beat this level normally.
Cake Walk - What Dave said for the most part. Block the fireballs with a block (you have tons extra). You can bridge over the ice to reach the left side if you want, which is a ton faster and uses less blocks.
Force Field - The left side of the level is easily completable, but there are only two ways to the right side. Make sure you know how to easily get back to these access points, as you will need to get them often. Also, don't watch the 970 AVI, it'll just make you depressed.
Mind Block - Build south to start, this will allow you to build back up. Once you get the middle section opened up a bit to where you can push the block in any of the 4 directions, it's just a matter of patience. Bonus insanity points for blowing up all the bombs, and super bonus insanity points if you fill all the empty spaces with blocks once you're done.
Special - Assuming you know how the level ends, just look at a map to see which blocks are hot. Failing that, just trial and error it I guess.