Though the tower idea is cute, this feels more like a very high level overview of how the level could look than the design of the actual level.
Instead of writing "the tower has a reasonable amount of floors", decide on an exact number and design all the floors. Why are there two floors that are just completely empty?
Don't overuse arrows. The "Boss enemy" label can be on top of the boss icon, no need for a giant arrow. Same goes for other instances.
There is a lot of text. Try to avoid it as much as possible and instead use pictures and one-two word descriptors.
I like the description of how the tower should look and feel. However it is rather randomly placed in the document, with no title signifying what the text is about. Also you don't need to write "the tower" three times in a row.
In general, avoid words like "should, could" and "there, that". For example simple "decoration and victory text" written on top of the tower is enough.