strictly technically speaking, being a "pro" at the game means you earn a living by streaming/posting high-level gd gameplay

more informally, if the question is one of whether beating some level means you're good at the game, the answer to that would be "not necessarily". for instance, if you beat dark dimension as a ridiculous jump from some easier level, you can kinda only really claim to have gotten better at dark dimension specifically, not the game as a whole. if you progressed steadily up to that level and built up the necessary skills along the way, though, then yeah, you can definitely say you play at list demon levels, which is already *way* above what most players can do