This is how Marvel's Avengers game should have been made.
It is a mostly linear adventure with just a few choices here and there, that do not really change the story that much, but may change certain episodes and dialogues. Your customization is very limited, essentially just perks, which you may want to collect, and costumes, that you may not really care about. But it has great story, and the way it's delivered is even better. That's what people wanted, not the service-game where main game-loop is grind.
Of course, there is a bit of a grind in Guardians, too: the fights. At least to me they started feeling a bit grindy, especially in chapter 14, which was mostly fighting. That said, though, while you do not have much (if any) combos, and the way skills are implemented, and the fact it's primarily a shooter (with guns not being that satisfying) may not be for everyone, I do think the interaction with the team was done quite nicely. There is actually a point in having team members nearby, since they have useful skills and you can target those. Unlike Avengers, where teammates were just smashing stuff randomly with no ability to ask them to do stuff. Although Guardians' AI is still not that good, and for me, most kills were done by me, and it looked liked sometimes teammates were struggling with dealing any damage.
Speaking of teammates... This game has a lot of banter. Which is awesome. Dawdle for a few seconds and you will hear teammates speak with each other or with you (that is Star-Lord), revealing interesting tit-bits about themselves or the world of the game. I really liked listening to them talk. But there was a problem with that, too: sometimes that banter got interrupted by something else and you would lose that dialogue forever (unless you restart a checkpoint). I really wish there was some way for banter to resume naturally somehow, but, to be honest, I do not know how that could have been done without heavily scripting where and when specific banter would start (and end).
I was not a fan of how dialogs on ship were done. The banter was fine in terms of content, but it often made no sense when characters were talking to each other while being on opposite ends of the ship. Often without screaming. But sometimes screaming. It still was better than the optional dialogues I got when interacting with collectables. Those felt to be added post-factum just for the heck of it, because animation very stiff and repetitive, which felt like a huge downgrade compared to the rest of the game. Voice acting sometimes was subpar, too.
There also were a few glitches here and there, mostly graphical ones. And also some moments where it was not clear what you need to do or that you could control the character even. The minigame with llama was weird, and I think there was another minigame, that felt out-of-place, too, but it was so brief, that I can't even remember what was the game.
But overall, again, good story and great adventure. Yes, it's not the story, that will change your life, but it is fun, it has some serious moments about the universal values, and even even touches upon some difficult adult topics. Kind of like golden-age Disney movies did, I guess. If you like the genre - definitely a must try. If not at full price (60 euros for 12-15 hours may seem expensive for some), then at discount - for sure.
