Reposting this from /r/Gemcraft. These are a collection of the discovered secrets in Gemcraft: Chasing Shadows. Some of this may be slightly inaccurate, but hopefully compiling all the knowledge here will get us closer to the final answer.
Grey Trees
ReaperGuy on the AG forums figured out GreyTrees, and Seberoth also identified some extra codes. It was discovered that the outside corner squares of the map (zoom out to make them easier to see) are clickable. Various codes inputted will do changes to the game, but so far it's only cosmetic aside from the almost-useless Gift Gems.
The codes are entered with the following scheme (as if they're four corners of a number pad): Southwest = 1 Southeast = 3 Northwest = 7 Northeast = 9
The codes discovered so far are: 11331791 - Grey Trees - To get the achievement, finish any field with this set. 11319773 - Black Orb 13371337 - Spinning tower shots 11379197 - Mossy towers 97713791 - Mossy amplifiers 77919713 - Heavy rain 79797919 - Heavy snow 77311973 - Gift gems 11799397 - Dark monsters 11111111 or any 8 digits of the same number - Mods reset
Assuming up to 8 digits in any given code, there are still over 65k codes to try. I don't think brute forcing these will work. Again, all credit for this discovery goes to ReaperGuy and Seberoth on the AG forums.
Compass
The basic gist is that you need to set all compass pieces to tier 5 and beat the final one that drops the field marker. Rinse and repeat 11 times for talismans and field markers. The third reward is a bugged field marker that prevents the round from finishing. Just manually end it and start on the next compass set. You'll know you have completed them all when the gems no longer show up in the loading screen.
The compasses themselves correspond to the gem tiers you see on the loading screen of compass levels. Teardrop is tier 1, triangle is tier 2, square is tier 3, a "U" shape is tier 4, and an "X" shape is tier 5. Every time the compass tiers reset, the compass correspondences are set to a random orientation, which always follows a pattern of 1-2-3-4-5-4-3-2.
Let me be perfectly clear: The directions on the compass don't matter for any tutorial/description, because where Tier 5 is pointing is random each time you do things such as reload the game, change your skills, or beat a level.
The compass levels, in left-to-right order, are C2, E3, J2, K2, O3, U4, and X7. The easiest level to finish at is E3, with only 24 waves at untraited Looming.
Here is my basic algorithm for setting a compass based upon the gem at the loading screen: Tier 1 - Turn 4 times. Done. Tier 2 - Turn 3 times. Recheck. Tier 3 - Turn 2 times. Recheck. Tier 4 - Turn 7 times. Recheck. Tier 5 - Done (duh).
With this algorithm, tier 2 and 4 always become a tier 3 or 5. Tier 3 always becomes a tier 1 or 5.
The rewards for completion of a certain amount of cycles is as follows: 1 - Field D6 3 - Bugged Field Marker (perhaps supposed to be N7?) 5 - Field O4 (Already acquired through normal progression) 7 - Field P6 9 - Field Q7 11 - Field X6 2, 4, 6, 8, 10th times: Talisman fragments of ascending quality
Missing Fields
This list is FAR from complete or entirely accurate. These are just the notes I have from field markers I have acquired or seen from other sources.
A6 - Complete A4 on Glaring B6 - Complete the achievement "Still Alive B1" D6, P6, Q7, X6 - See compass explanaition above. Y4 (->Y5->Y6) - Complete all waves on X5 without charging up the gem. G4 - Complete the rest of Hex G on Haunted difficulty L5 - Complete L1, L2, and maybe L4 on Haunted difficulty
How the hell do I get the inner talisman fragments with 100 rarity - I can easily get the outer ones at 100, but inner ones seem to be very difficult to come by and most of the time they are 90 - 99 rarity, I've only found 1 at 100...
So i always found the compass quest a little too boring ......not worth my time. But i finally decided it was time, just to wrap things up so to speak, and do those last couple of levels that you get from the compass.
first round......no problem
second round......no problem, got the fragment.........but now it seems the compass settings didnt reset. They are all still showing the 5th level. even tried from a different computer.
on the second round i just did the compass spin and left without beating the level. that seemed to have worked since i got the fragment. With it not re setting though, i went back and beat each of the levels . That didnt help.
When all marks are set to g5 gems, enter a field, click on the compass till you get reward and win the battle. That should work. You have to win the battle when clicking on the compass gives you the reward.
For those that completed the Flea Trap achievement, how did you do it? That's my last one.
Kill 45 monsters while your orb is blinking.[b]
You know when there's so many monsters in a line that your gems can't keep up? It's about that. But when their being banished. Ifs like the last time you could ever hit the monster before it reappears.
Each time you set all the compasses correctly and beat the level, you will receive the following rewards, in order (rarities can be boosted with shadow cores, as normal):
Fields D6 and H6, talisman fragment (rarity: 34) Fields N7 and P6, 2 talisman fragments (rarity: 42, 58) Fields Q7 and X6, 2 talisman fragments (rarity: 65, 73)
from : http://gemcraft.wikia.com/wiki/Mysterious_Compass_%28GC2%29
