Sometimes there is too much content shown, but I don't mind it as much as I do movies. A game is what you can make of it, just as much as it can offer. Someones 10+ hour playthrough will likely differ from someone elses, if the game allows it, that is. With movies, seeing or revealing too much can really ruin the experience since it's much shorter and relies specifically on giving you a good story. Like Terminator Genysis. That isn't really a good movie, but how much more impactful would it have been, and a boon to the movie, if John Conner wasn't revealed to be a Terminator until the right point in the movie, compared to being shown off in the trailer and all the advertisement?
For games, it depends on what it is for me. Is it mostly a story driven game? Then I want to see as little as possible. Is it an open world experience? Maybe just keep some gameplay surprises for me. I generally watch the reveal trailer, gameplay trailer, and then I'll see stuff off and on, but I don't watch much more gameplay after that if I can help it. For me, the only things I don't really want spoiled, are story related things. Learning a mechanic or feature ahead of time isn't a super big deal personally.