Works as advertised, when used as directed!
I used this to remove concrete splatter from the side of my house, 6 days after it happened.  The key is, it needs to be DRY - don’t wet the concrete with water first.  A small shot on it, wait 5-10 minutes, and the concrete was liquified, wiped clean with one swipe of a dry rag.  Amazing stuff!
Rating: 5 stars