@Dzik Same in older Slovene texts. Even after Bohorič though, writers would use his orthography but add letters or disregard his rules. Apparently even Trubar, another Protestant scholar and Bohorič’s contemporary changed things up a bit. As for the upper case letters maybe you’ve seen both u and v having V as their upper case version (Vu and Vv)? So Ucho/ucho would be written as Vcho/ucho, but it would still be read as a u in both cases. I think this was very common across Europe. The Italians still do this with public signs, for aesthetic reasons.
Indeed, the fact that it uses only basic letters (except maybe Ş and ſ) is neat. Also, did you understand our Oče Naš when you read it? Are you able to read the words without too much trouble if it is written this way?