Thank you very much! I am interested in what people think of how the game works, so even if it was not marked, comments such as yours are valuable. :)
If you have seen the film Tenet, it may help a bit understanding the reversed entropy/timeline. I was not expecting the first level to be that difficult! Maybe this is because it takes time(!) to get used to the concept; I think the game is rather hard, although several levels are basically tutorials. Some levels are somewhat tough, I occasionally had to think them through to solve them again when I was testing. ;))