I am with you, and also a backer. The original goal was exceeded by a wide margin (£12,927 pledged of £3,500 goal). 12K GBP is a non-trivial amount of money. There are no videos (if you exclude a low quality recording of a talk on the project https://www.youtube.com/watch?v=LVM8N0eH9Qk), no screencasts and the text only covers a few of the topics outlined in the campaign.
Either of you please email me with your backer number and I can refund you or turn what you paid into a donation to Médecins Sans Frontières if you are not happy.
I am very pleased with what is there so far, think it genuinely captures all the best bits in an accessible way. I am most proud of the Escher and Evaluator bits and associated projects.
I have lots more partially complete, feel I have a fair bit of momentum now and do still intend to make videos as I said in the update to backers, backers will see them first. I am genuinely sorry it has taken so long to get this out.
I think I was quite fair minded re: pricing etc during the kickstarter. I changed it from a sliding scale to allowing unlimited people taking the lowest amount (£20), then created a 'pay what you can' tier and invited people to switch to it if they wished.
It seems like a communication problem. If you're still going forward but don't push sub-par content out in the public due to pressure, this is acceptable; but if people don't know (I can't read the KS status updates, but there's not many of them) they'll be angry just because of that.