Even if we've spent a good amount of time defining our levels, some imperfections creeped in. Here's the list of known issues in level definitions affecting the current version of the software:

DragonBox+ / 5+

• Chapter 3 Level 6: the game gives 3 stars for the solution 1 + (-1)*worm = box but only 2 stars for solution 1 - worm = box which is cleaner but takes one more move. Reported here. This will be fixed in a future version (not 1.1).
  

Training pack

• Chapter 1 Level 11: the game forces one to add numbers together to get the best result, but this new rule hasn't been taught yet
• Chapter 2 Level 10: the game accepts c+c and turns it into 2*c but takes one move
• Chapter 3 Level 15: the quadratic equation x^2 = x/3 has both 0 and 1/3 as solutions. The game only has 1/3.
  

DragonBox Algebra 12+

• Chapter 7 level 10: the game can end up with 4 = 5: On purpose we have designed levels where you happen to come to a contradiction if you perform an operation that is actually illegal when solving equations. We want the player to discover it and ask questions instead of being told not to do it.