This new style is a very bad news for me, because it lacks much more tools I find useful for learning languages than the old version of Duolingo. And of course, it looks like a big mess: every good book or web page has a content, an easy guide to see it all and navigate through it exactly where you need to go - there is absolutely nothing like it in the new version and it shows even much less overal view of the course than the old one.
1) I had 2 finished courses on legendary level. Both of them got less numbers than the original number of skills was in each of them, and in each of them I was now asked to do one lesson to rise from golden to legendary. In both off these languages, I got the easiest tasks imaginable (something like Level 1 in the old courses, but sententes from all over the original course), 40XP for finishing them and the courses became blue=legendary. There are no broken legendary skills any more, but you can get, what you "need" to practise by clicking on that moving symbol on the left. Unfortunately, I always get Level 1 difficulty tasks and the simplest sentences, which is useless. Lessons are organized in a different order now and it is really hard (ot better to say - impossible) to find the topic you need to practise (i.g., past perfect or other tenses, vocabulary about traffic etc.).
2) I do not like the idea of mixing stories into the course line, because they do not match the knowledge level achieved in the course before them: they contain much more advanced grammar, lots of unfamiliar vocabulary... (thankfully, you can at least let duolingo show you the proper translation of each word in the story sentence). But you cannot skip these stories, because some words from them are used in the next lessons. I quite wonder though, how they solved the fact, that the old version used one synonym in lessons and the other one in stories (e.g., "soccer" in English lessons and "football" in English stories).
3) My progress in two unfinished courses has changed without any logic, as mentioned in discussion above. In one of the courses, I was offered a test to achieve the legendary level, but it was just to lose 10 lingots, because I have never seen any of the sentences in the old course and never learned that vocabulary. As the sentences and "skills" are now in a completely different order, it does not mean you know already everything what is "behind you", when you are standing in the middle of the course. The only way to continue study on Duolingo is to throw away everything you have done so far, all your notes and vocabulary lists and start fresh from the beginning, which is - after months or even years of everyday learning - not pleasant at all, to be polite.
There is still a back-up of the good old Duolingo here: https://www-internal.duolingo.com/learn However, I was warned that it does not record your progress any more. But you can still earn XP's in it for stories etc. , that appear to be counted in the "snake" version too. You can still practise specific skills through your profile on Duome too. When these last remains disappear and the "snake" will be the only way you can study on Duolingo, I am leaving (although I am not happy about leaving behind all my achievements including being listed in Duome halls of fame), because I will not learn anything this way and clicking games based on good luck are not my style.