There was a Dutch guy who popped into the Sera thread a couple of times, but that was ages ago... Dutch and Nordic people almost always impress me with their level of English. I remember being on holiday years ago when a Dutch kid told me how bad he was at English. In near-perfect English. I understand it's partly because you get TV-shows and films (and I guess video games) with just subtitles instead of being dubbed into your own language, so you're all constantly exposed to it from an early age. Of course that must have just been amplified these days with the internet.
Well, I've never played video games with Dutch subtitles or voices, even though I'm sure there probably are. I guess it is mostly that, yes. At least, my English has never benefited that much from English class in school, save for getting a better understanding of grammar and why some sentences are structured as they are - which probably would've come to me naturally anyway, due to this exposure to so much English content, both on- and offline.
Holland (or the Netherlands, if you want to be correct) is a small country, so it's only logical most of our media consumption is English - from which we benefit a lot 