why do all the push blocks only move up/down?

i'm totally lost in level4. been to every room on the map. can't figure out how to get into either of the "eyes" - seems like i've tried bombing and walking through every possible wall. is the whistle the dungeon item? not really a fan of the design of this level, too many random bomb thru walls. oh, i hit another dead end, time to start bombing every possible wall. i've had to leave the level 3 times now to get more bombs. should be more rooms that drop bombs for killing all the enemies - or maybe some enemies with bombs in their drop set. the super strong didongos just rub salt in the wound.