XXX etc.

I think you'll catch on to the big idea of this puzzle rather quickly. . .but still struggle with some of the answers. Truth be told, creating a crossword puzzle presents multiple layers of difficulty to a constructor (that's me) as well as for the solver (that's you). Nonetheless, I hope you enjoy the struggle. Good brain workout, I think.

Click to print the puzzle or the solution, or solve the puzzle online at crossword.info/drpete