The secret 4 panel can be done pretty damned easily, actually. I got it done on accident before almost any other achievements. First time I got to 11 I think. Anyway, if you have a few bomb powerups, Line Bomb and remote detonate, get to a place where you have a few long rows completely open, set a few line bombs in a row, and then tap b faster than the explosion can catch the bombs. This is how I did it, I got the power up, and had 300+ health by the end of the level.
BTW Thanks for the post I'll have to go back and work on getting those other ones.