It's easy to show a "working" prototype when it really isn't, through very simple video sleight-of-hand , especially with selective framing on partially built prototypes. Just watch and ask yourself what parts aren't in the frame of the video at the same time, when it's being used?

That they had to post a new video to more properly represent actual speed, if they were trying to be honest, why wouldn't they mention the speed-up in the first place? If a backer's going to get bored watching actual speed video, then they're going to get bored with the actual product - one apparently designed for looks first and functionality second - assuming they can get that to run off of a USB port.

Engineering companies have done worse.

The problem with taking the generous side and saying they did things in "beginner's lack of experience" is that it bodes poorly for the project as a whole.