My favorite video game from the year 1990 is probably
Devil's Crush. It's a fun pinball game that has cool aesthetics and theming and also has a great soundtrack. Not only is it fun, but it has some nostalgic appeal because I watched my older sibling playing its Sega Genesis port, known as Dragon's Fury, when I was young. The cover art of Dragon's Fury is also etched in my brain since I thought it was neat as a kid. You can check out the gameplay here (gameplay starts at 0:31 in the video):
Honorable Mentions
Columns: A puzzle game that's kind of like Tetris but with gems. It has sentimental and nostalgic appeal to me since it was one of the first games I played, and also because not only did my older sibling and I play it, but even my mom played and enjoyed it occasionally and she's only played a few video games throughout the years. The soundtrack, though very limited, is also memorable for me, particularly the song
Lathesis. It doesn't beat out Devil's Crush for me since the gameplay doesn't really stack up to other similar puzzle games like Tetris or Panel de Pon since you can only rearrange the gems in a vertical line. It's still fun in its own way, but yeah.
You can try it out if you have either Nintendo Switch Online + Expansion Pass as part of the Sega Genesis section, or it's also one of the games included in the game Sega Genesis Classics.
Alien Storm: A fun little side scrolling beat 'em up with a neat alien invasion theme and includes some gallery shooter sections. I'm not as attached to this one, and there are definitely other beat 'em ups I prefer to play, but I think it's neat. Like previously mentioned with Columns, you can try it out if you have the Nintendo Switch Online + Expansion Pass or if you own the game Sega Genesis Classics.
Fire Emblem: Shadow Dragon and the Blade of Light: This is the first Fire Emblem game. I'm not as attached to this one either, and it's understandably a bit janky to go back to play nowadays due to all the gameplay improvements made to the series as the series went on. That said, at the end of the day it's still a serviceable turn-based tactical game with knights, mages, dragons, etc. and actually has a plot, and all of that stuff appeals to me. I also owe it a debt of gratitude since my two favorite games wouldn't exist if this game hadn't started the series in the first place, so I feel it deserves the mention.