Mazowieckie, PolandSo it looks like this game is bugged in Ruffle, according to this forum thread @ TASvideos:
As it turns out, ruffle isn't emulating this game correctly. You know how in Level 2 there is a moving block obstacle with spikes that can kill you? Well, there is supposed to be more of these throughout the entire game, but for some reason, most of these blocks get shifted to the very right edge of the screen at the end of a level, making the game (unintentionally) easier. Thing is that this isn't supposed to happen. Level 4 skip somehow still works on Flash Player though.
This also means that the version on Flashpoint should be recommended instead (SHA-256).
No issue on GitHub for now; if someone has a GitHub account, please open one here.
Also, maybe there should be a guide on how to unlock all levels? It can be done without modifying the game itself.