Call me dumb, but what are illegal moves???

[drevo77]

I wasnt aware of illegal moves.., until I tried one of the treasure chest challenges? Anyone help me out please? thankyou!

[coolgamegirl27]

An illegal move is a move which doesnt make a matched row or column

[SarahD05]

Call me dumb, but I new help on level 17. What exactly is meant by the goal "combine 2 blasters"? I've tried everything I can think of and nothing works!!!

[drevo77]

Thanks!