Secret on lvl 3 and all levels from 5 are way to vague. Like, the sudoku secret should seem obvious with the red -1 but no clue. On the third level i got to the 0 level with reaching the exit with 0, but no clue what it meant or if there's a solution. I thought i had the 78[x]62,46,38 solution too, stepping on with 70 but that didn't work and it was tedious enough to get there. The 6 battery in the corner level the solution seems to be related with the recycle battery sign but since i didnt figure it out the first time...
Anyway. The game itself is well made, but way too cryptic for the simple folks. Since when i need to be good at videogames. XD