Idea is decent, although execution is a bit lacking.
The tongue is unnecessarily slow in my opinion, and gets easily bugged especially if there's more than 1 box around. I got stuck and started floating on several occasions. I also didn't at first realize that the tongue flies all the way up to the mouse, so I thought it had a very short range.
The platform in the center should have a special texture to indicate that it's possible to grab it with your tongue, since it looks the same as the walls and you can't grab the walls, I thought the platform was just another wall.
I think the theme would come out better if you weren't able to jump, and instead had to grab the ceiling or wall where you want to move to, or even better were able to swing from the ceiling using the tongue. You could also put the oxygen tanks on shelves or something so you'd need to use the tongue to grab them.