Regardless of me not really being a fan of the game, I don't think this should be added.
Cube likes to be somewhat original with their games, and this is one of those games where you really can't put a good twist on it. Money walls, a previously removed gamemode, was similar to this gamemode and was removed due to multiple factors along with the fact that it had the unoriginal falling walls aspect. I'm not saying that the walls part is the main reason to it being removed, but it definitely was an option.
I'm honestly surprised that a few of the people above hadn't heard of the walls before. It was one of the most popular minigames back in the day, and googling it really isn't that hard.