For falling faster: Make something like this
On downarrow down+Platform:in air(not on a platform): Move the hero down. I can't explain it different.
For the blocks: First method. make 2 bounding boxes, when 1 of the boxes, the upper one, is collided with the hero it destroys. Second method: When the Hero's Y is higher than the block's Y and they collide => destroy the block.
Good luck finding a graphic designer