One of the most unique games I've played in over a year. It's not as good as some people make it out to be, and I still had a better time with Fallout 3, but there are some really strong moments to be found.
Charm oozes from the simplistic visuals, isometric camera angle, NPC interaction with models made out of clay, the industrial, ominous background music, detailed UI, and overall aesthetics, which the franchise always excelled at.
The premise is simple, but well explored, especially for 1997, and I would argue that the quality of the narrative is more consistent in comparison to FO3. The quests aren't as creative, and it usually boils down to killing a group of enemies in another location or picking what faction to side with, but I like how there still are multiple ways to handle various conflicts, with multiple consequences, to make the world feel more alive.
The first area of the game SUCKS, it's not difficult as a concept, but it's unplayable if you don't make the right starting character, something that goes against the very concept of an RPG. It get's easier after you leave Vault 15, and the rigid, methodical and almost unpractical gameplay become more familiar. However, there were plenty of points were the difficulty became plain unfair and frustrating: NPC's would make me get stuck on a hallway because they would not move, the stupid dog who you can't control at all would get himself killed, allies would shoot me, and sheer luck from the dialogue and combat choices. I found myself using and abusing the save system a lot, which broke the immersion.
Some particular aspects that I really liked: The voice acting as a whole, Necropolis and Boneyard, the main antagonist, final cutscene, the caravan system at the hub, the fair time limit, sense of freedom.

Holds up well on replay, even better with a controller. The movement is not as good in comparison to other Mario games from the NES, which makes sense since 95% of this game is from a different IP, but outside of that, the non-japanese SMB2 is a pretty clever and fun evolution of the platforming genre.
The level design is pretty good and the colors are great, the music is catchy and atmospheric. There is a decent variety of settings, enemies and bosses, which makes progressing through this title much more interesting than SMB1.
There are plenty annoying and unfair sections, so I found myself either skipping parts of this game by using Luigi (game breaker) or by abusing some wall-glitches, and I guess that makes this game not as fun as others from the franchise.
I enjoyed the verticality of the game, and the new gimmicks it would often try out. Wasn't a fan of the life system, and that includes the cherries, the hearts and the coin system. The potion is a cool concept but it should have been used in better ways I think.
The bastard child of the NES Mario trilogy is a creative, aesthetically pleasing adventure that was responsible for a large amount of ideas that are still present within the franchise. The difficulty and clunkiness are annoying, but it's very charming from top to bottom.