Everything you're describing sounds possible in Decker, though some of your ideas will require quite a bit of scripting!
One idea for representing complex collision maps is to draw the impassible walls using a specific color or pattern. You can then copy a chunk of the card background and use image.hist to see if any pixels within that chunk contain the collision color:
if card.image.copy[pos size].hist[collision_pattern] # ... end
You can use a vibrant color during development, and then replace it with a color that looks identical to black (or otherwise) when the maze is done to hide your collision boundaries from players!
There are some constraints on which keys you can use, but the gamepad interface should be handy for building any sort of action sequence or minigame.