I really enjoyed this presentation. It is interactive and has a great check and redirect component for review and mastering of the grammar concepts. I really liked the funny play on the sentences when the commas were missing or in the wrong spot.
One area that might be helpful to add is the pen tool so students can mark the sentences where they think the comma might before they select an answer, this would help your visual learners. Sometimes it helps to see it before committing to the answer.