Interesting video, and unlike a lot of prior stuff that Moller/Freedom Motors has done in the past, it doesn't look amateurish or half-assed.
Paul harps a lot about the effects of acid (from the combustion of hydrogen sulphide) on the lubricants of a more conventional engine, but this is something that can be addressed by the choice of lubricants. If you're running an engine on sour gas/biogas, you choose a lubricant for that application, which is designed to counter this acidity. (At least in this video, they acknowledge that such engines actually exist).
With regard to "catching cow farts" -- what actually happens is that the cattle manure (which also emits a lot of methane) is gathered in an anaerobic digester. This breaks down the manure and generates methane at the same time. (Unless Paul is planning to make portable units with the 27 cc rotary engine for attachment to individual cows). The methane that results is usually burned off in smaller operations -- they propose a Rotapower-powered genset to consume this methane generating electricity.
I suspect the reason that this crowdfunding is doing better is that it isn't targeting "the Moller millionaires". Instead, they've come up with a good pitch (on video) that works on a wider audience, as well as having a smaller and more realistic objective than past crowdfunding attempts. To be fair, I'm probably unduly jaded about the website material compared to someone seeing it for the first time. Combined with the video presentation, it may look pretty good to someone that isn't familiar with Moller/Freedom Motors less-than-distinguished track record.
