This is some really great feedback, thank you!
Regarding the rope shortening: yes, that was a conscious decision. I prototyped a lot of different things, including what you mentioned, but I found that playtesters moved much slower when the rope was not shortening automatically. They were often just dangling on a long rope and didn't really do much. This didn't feel good to me, so after countless iterations, I settled on this. The current system (hopefully) encourages players to keep moving from hook point to hook point and allows them to go even faster by hitting W.
Regenerating health is definitely planned and will highly influence the game's difficulty. Dying should be an essential part of the experience :)
Variance and Giant level are not very well made yet, you are totally right! Gotte improve those! :)
... and your English is totally fine! But I'm not a native speaker either :D