Kickstarter pages are not product descriptions. They are ideas, or visions for what a product / service COULD be if they receive the funding. They are not guarantees of features or even a completed product of any sort. Kickstarter isn't store where people advertise their cool new products for sale. You weren't buying a product. You were funding a possibility.
You are upset because they had a concept for a feature (motion tracking, object avoidance) that didn't get implemented. It's perfectly reasonable to put out a video of what "could be" if the product was funded. It's not a guarantee of what will be done if the product is funded. Maybe do some investigation into what it takes to bring a hardware / software product to consumers. It's f****** HARD. Companies fail at it all the time.
Like I said, looking at their promo materials and progress it's pretty clear they made a reasonable go at it. It wasn't a scam, they just failed.
I'd suggest not involving yourself in Kickstarter. If you like an idea, wait for it to come to market. Follow independent reviews of the product to understand if it will meet your expectations. It's the course that most consumers follow.