My father likes both Zuma and the BTD series of games, so I made this for him for Christmas. Figured it'd be a shame to not upload it anywhere, especially since this site apparently exists.
Believe it or not, this wasn't inspired by the Monkey Lane mod already on this site. I didn't even know it existed when I started making this!
To install, just replace your existing levels.xml folder with the one linked on this page. Don't expect it to be incredible, this is my first time ever making anything decent for this game (there's probably a lot of garbage in the files but it doesn't matter because the game works I think.) The odd selection of levels is because I didn't know how to make tunnels when I started making this mod, and figured out how way too late into its development to go back.
Credits:
PopCap Games for Zuma Deluxe and related assets
Ninja Kiwi for BTD5/6 and related assets