maybe pin a sprite above the character to detect solids.
create Sprite "solidsensor"
10 by 10 pixels. invisible.
on layout start: set position to player.x and player.y+30
set pin to active
if solidsensor collides with "blocksprite," set global variable "moveupallowed" to 0, else, set to 1.
on key pressed "up", (when moveupallowed =1), move player up.
maybe that type of logic would work?