He seems to create a lot of straw men and then claiming he has defied economics by showing those examples turned out wrong.
I am not an economist but I remember from the basic textbook that nobody actually knows the supply and demand curve. So his claims that economist predicted explicit values for tobacco seems unusual. Also his example of more poor people ending up smokers than rich people - does he think the numbers would be reversed if smoking would have remained cheaper? Also even if prices were increased via taxes, it doesn't mean demand could not also be increased for some other reasons? People don't smoke because they want to spend money, after all.
Minimum wage of course comes up all the time. Here in Germany (which is also mentioned in the article), I don't thin unemployment is measured in a very concise way, as it is also a political number. Politicians want to be able to say unemployment went down.
So there are lot of people who are not actually being counted in the official number, like if they are not actively seeking employment, or only doing side jobs. Minimum wage increases usually are also not that high. I think there might still be jobs lost, just not those that are being counted. An example would be a pensioner doing a side job to earn a little extra income. If her job falls away, she doesn't file for unemployment because she already is a pensioner. Student jobs might be another example.
I guess it is true that it is difficult to predict some things, but surely, if you can present a theory that is good at predicting, it would make a dent in economics? No need to declare classical economics silly and claim to be inventing a new kind of economics.