The main mechanic is super unique and I love how the items and gameplay tie into the narrative. The level progression is also nicely designed too - each level teaches you something new to build or break, and you use that knowledge for future levels. The swap mechanic is also a godsend, so I really appreciate it being there.
I'd make it so that holding down the arrow keys would move the player faster. It gets pretty repetitive mashing down one direction to move long distances. I'd also use a different object in place of the ham, as trying to spell "Hammer" can get you ham instead. For the last level, I'd probably remove the purple cage entirely, since the last level feels quite long and tedious already.
Overall, this is a very touching game and I'm glad I got to play it. Well done!