This is exactly why I always say optimize at the get go (graphics and physics, not just code/scripting). Just because it's fast in development doesn't mean something else won't be later. Building a base foundation to work on that's solid, and testing at each iteration, is very important - to prevent this very thing.
Oh, and by the way, they claimed you can make mobile games, and you can, so it's not a scam. Just because YOUR game doesn't go fast doesn't mean others are not. It all comes down to what kind of game you are making, and the amount of processing (GPU or CPU) required. You have to work within the means of the application. Plenty of people here are having lots of success creating their games within the means of what C2 can do, so again, you have to be fair about your expectations.