Always nice to see a big-name release coming to GOG.
However, I also played this one already on Steam and was very disappointed. I agree with nightcraw1er.488 that the first Stranger Things game that accompanied the second season and came out on mobile platforms was fantastic, definitely also one of the best mobile games I ever played. Great visuals and audio, cool levels and puzzles, no ads/in-app-purchse/pay-to-win BS. And a game that has a true ending and 100% goals, not something that wants to keep you in the Skinner box indefinitely. One of the rare mobile games I would've gladly paid money for, had it not been free.
I hoped Stranger Things 3 would be a bigger and better version of the first, but it's worse in almost every way. The visuals look like a cool, bigger version of the first, but when you actually play the game you notice how poorly the levels are designed. The locations in the mobile version looked kind of realistic and similar to the places in the show, but in this game, they are huge empty spaces lacking in detail and feeling completely unrealistic. The kid's basement is unrecognisable, houses have industrial-sized pantries, etc. It really fails at taking you there.
The storytelling is also nothing to write home about. If you haven't watched Stranger Things season 3, you will be completely lost at what's going on. It only references the show, but doesn't explain the plot elements to those who don't already know them. It also doesn't offer anything new, instead it contradicts the show in places and shoehorns in very silly tasks that don't fit the characters. So the story is really bad for everyone. For fans of the show it feels like written by someone who doesn't know Stranger Things, and for outsiders it makes no sense at all.
It's a cute retro action puzzler that doesn't look and sound too bad, while being completely bland in the plot and mechanics. The original worked on its own scale, this one feels like only the scale increased but without the necessary additional content and care to fill it. It's not terrible, just so very, very disappointing. I guess it can be worth the price at the current discount, but definitely not for the full price that I paid.