Hasn't aged that well compared to subsequent remakes. Little was done to actually improve upon the story details from the original games, aside from the addition of a few small islands it's mostly the same as Red & Blue but with GBA graphics. While the originals excuse was lack of space and hardware limitations, it seems like there was a lack of imagination with this one, especially in regards to legendary Pokémon. This also lacks the retro charm of the originals and feels more generic in style. In the attempt to modernize it loses a lot of its identity and what made it unique in tone, but this is a problem most of the remakes have.
Ultimately it's a necessary game for completion of gen 3 and as an extension of RSE it's a serviceable companion but ends up feeling a little underwhelming for me personally.

Bungie's swan song. What a way to go out.
It's light on character development with the focus mainly being on the fall of the planet Reach. Marty O Donnell's grand score and Bungie's cinematic approach to cutscenes are masterfully done here, it all works together to evoke strong emotions. The use of a silent protagonist as a faceless observer gives the player quiet moments to reflect on the tragedy and loss of the war, they're personally some of my favourite moments in any game and it was only heightened knowing this would be the end of an era for Halo games.
Multiplayer proved very divisive at the time but I personally enjoyed it about the same as I did Halo 3. Had to have been experienced in its heyday to really get the full effect.

If it wasn't for the inclusion of WiFi battling & trading (which doesn't work anymore) this game would've been a mediocre sequel. Many of the new monsters I personally found underwhelming in terms of design, this was the first time a game didn't motivate me to catch a full team. The battle gameplay is slower than its ever been and I found much of the map forgettable. I've heard Platinum was better but this didn't leave me wanting more of Sinnoh. Once again features locked events only accessible via hacking.

What I liked about this was the effort put into overall visual presentation and the attempt to do something different with the formula. Problem is the game makes itself far too easy with excessive hand holding and most of the new creatures follow a sugar coated cuter-and-rounder motif that I got sick of pretty quickly. I found the surrounding characters and region more memorable than X & Y but at the same time they were more cringe worthy and annoying. Basically, this feels the most preschool of the lot but the competitive side of the game still exists for veteran battlers.

Ignore the zoomers. This game was basically a system seller for the GameBoy and was made for a very limited handheld system with all of its limitations. Inevitably perspectives are going to be skewed for those playing it for the first time on modern hardware. It was revolutionary for the time and birthed a franchise and template that's since been reheated and retooled for decades. Judging it from a modern day perspective is difficult as we've since been spoiled by prettier graphics, more complex music and various gameplay improvements. While I do think certain games in the series have improved upon this, I still think the gen 1 games hold merit for their retro charm and the fact that they're the purest form of the Pokémon formula (before any gimmicks started to be applied). The core game is more challenging than modern entries and it does not hold your hand nearly as much which is something I appreciate.