I always found myself playing this one as a kid, but never actually played through a full game... so I did it in about 50 minutes.

The main takeaway from Baseball is that its AI and instruction is very odd. AI itself seems to be the common complaint with this one, especially for those who rely on it specifically because they didn't fully learn things in the instruction manual. I noticed difficulty against the opposing team either ramping up in the later innings or just fluctuating entirely, which is frustrating. Even found certain points where some of my players in the field would run past a certain point, making it longer to retrieve fly balls.
As for the instructions themselves, I personally had to look up the manual online, and even those given controls didn't feel as good as I wanted. Pressing certain combinations of buttons to guide your players to bases is confusing, and it's not really something you can get used to over time.

Baseball is a cool little NES title for its time sure, but it ultimately feels more like a Nintendo toy than a practical video game. Doesn't hold up too well, unfortunately.