I’ve added a review here: https://online-go.com/game/11591047
I think that, by move 50, it’s probably too late. If black just plays solidly and consolidates everything, they’ll win by a large margin. There’s some reduction potential from both players, but the major mistakes have already been made. Most of those mistakes come in the form of small moves that don’t give you much of anything, which your opponent uses to build his moyo.
The biggest example of this is the sequence from move 14 to move 28. You play 14 moves without really enlarging your corner at all. That corner starts looking fairly alive and worth about 10 points, and ends looking alive and worth 10 points. You’ve got some stones on the top, but they’re too weak to really hold that territory if your opponent attacks them. Meanwhile, your opponent has almost completely surrounded your corner, and has a massive wall pointed directly towards the moyo they’re trying to build. The sequence from 38-40 is similar: you’ve added maybe 10 points to your corner over the course of 3 moves, all of which encourage your opponent to build his moyo.
Especially in the beginning of the game, ask yourself, “does this move kill something significant, save something significant, or give me a bunch of territory or influence?” If it doesn’t, look for a bigger move. Moves that seek to enlarge your territory while putting pressure on your opponent are especially important. Even if your opponent gets a big moyo, so long as you’re consistently making moves that enlarge your frameworks by at least as much, you can still win the game, even if your opponent doesn’t screw up and lose a 30-stone group.