Really solid game! I was messing around with a block placing game myself before the jam - didn't think of using it in the jam, so good job being creative - I hadn't thought of using this idea for the theme, but it makes sense in your game! I really like what you have - a lot of really fleshed out and polished UI, so that's awesome! I would love to see how you would expand on this game.
A couple things to note: The texture of the rock was missing and the shadow of the cactus looked a little off.
Otherwise, great game!