Hey Dadpernia,
I'm sorry to have to tell you that your map has been REJECTED. The theme, by technicality, could be viewed as we have no "Grandpa's Ladder Parkour" themed maps or any solely ladder themed maps for that matter. But, we do have various Minecraft block themed maps and a "MelonLadder" themed map which bears somewhat of a resemblance, making this a rather unoriginal build. And, it's really just not a great theme at all. The build is not good due to the floating aspect of the build, lack of focus, and poor block choices. Regarding the parkour, it fits the medium difficulty difficulty-wise but not length-wise at all, it needs to be shortened. And, it lacked proper variation. You should procure to use a variety of blocks/jumps so that your map is enjoyable to play. I hope you will take these criticisms into consideration in your future map submissions!