I found these two achievements pretty difficult, so I hope this helps someone else. This covers Death Defied specifically, but you should get the other one while practicing. Nothing here is super consistent unless your timing is the same every time, so don't get worried if you have to restart the level a bunch.

• Choose level 4.1.
  
• Try to keep your players centered (as in, 12 o'clock and 6 o'clock) for about the first half. You can change where your characters are by timing your jump when you enter the next circle - do it early to move the bottom one to the right, or late to move the bottom one to the left.
  
• The first hard part is the circle halfway through with the enemies who switch between inside and outside. Try to enter this circle so your characters will have to travel about 90 degrees to get to the sector of their color. It helps to have the bottom character a little left of center when you enter the previous circle (with the 4 flying enemies). Depending on exactly when the enemies switch places, you'll have to alter when you have your characters enter, but with the 90 degree thing it should usually be possible.
  
• For the next two circles with jumping enemies, if you're lucky they'll be set up so they jump when you pass them and you can just enter at the end of the timing window. If not, enter right when you pass the middle enemy and then immediately jump, and that often works out.
  
• After this there is an empty circle, and then 4 of them with an enemy walking around and some stationary enemies. The most important thing is to dodge the stationary enemies, so for the first circle you want your characters to be a bit off center, and then for the next three you want to be as close to centered as possible. As far as the walking enemy, first enter with the character of the color behind it, and then the other one, then jump over that enemy. Sometimes that jump will immediately enter the next circle (and hopefully the angle works out) but usually it won't, which means you can then time the entry into the next circle with another jump.