I definitely agree that the copy is a bit too casual, and not only because of the vocabulary, but also because of the punctuation just like in "Holy smokes!!!!!". It is actually "incorrect" to use multiple question marks and/or exclamation points. It's like misspelling a word. I would recommend removing the extraneous punctuation and maybe change a tiny bit of wording ("pain in the ass" is a really ugly expression).

On the good side:

- GREAT idea

- Simple, clear and easy design

Keep on the good work!