The PS3 generation was certainly a strange one for PlayStation, but there were some incredible exclusives on that console. Unfortunately, the PS4 and, eventually, the PS5 aren't backwards compatible, meaning the only way to play PS3 games on a PS5 is via cloud streaming. Not only is that a terrible solution for these classic games, but it also means the available titles are limited to what the PlayStation allows on the surface. The best way to get PS3 games on the PS5 seems to be waiting for PlayStation to make an upgraded PlayStation 5 version, similar to the treatment Demon's Souls got for the PS5 launch. For this list, we went with the obvious classics that can't be played anywhere else unless you cloud stream. For the sake of simplicity, we bundled multiple games in a series together if there are multiple PS3 exclusives that need porting.

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The missing puzzle piece
If you have never played a Metal Gear game, you can almost play the entire series on the PlayStation 5. The one caveat is that Metal Gear Solid 4: Guns of the Patriots is stuck on the PS3 due to exclusivity. Not only is a game missing, but it's one of the main numbered entries in the series. While MGS4 has been critiqued for being made up of too many cutscenes, it's still a beloved game and crucial to the plot of the series. It seems possible that a solution could be coming soon, as Konami recently released Metal Gear Solid Master Collection Vol. 1, which included Metal Gear, Metal Gear 2: Solid Snake, Metal Gear Solid, Metal Gear Solid 2: Sons of Liberty, and Metal Gear Solid 3: Snake Eater.
There have been rumors of a second collection (via Kotaku), and calling the first collection volume one indicates a plan for a second collection. Considering the first collection cut off at MGS 3, the next collection, including Metal Gear Solid 4: Guns of the Patriots, seems likely.

Metal Gear Solid 4: Guns of the Patriots
3 Drakengard 3
After Nier Replicant, this seems like a logical next step

Source: Sqaure Enix
Drakengard 3 is a hack-and-slash PS3 game published by Square Enix and directed by Yoko Taro. The game follows Zero, who is set on destroying the Intoners. Not only is this an excellent hack-and-slash game, but it also features excellent music and a strong narrative. It also ties into the Nier series, albeit indirectly. The short version is that one of the endings sets up the post-apocalyptic world in the Nier series, confirming they take place in the same universe. The narratives don't tie together beyond that, but Neir contains a ton of DNA that was built in the Drakengard series.
At the moment, Drakengard 3 is only playable on a PS3, making it extremely difficult to play the game without original hardware. Not only does Square Enix still exist, but so does Access Games, the developer, and Square Enix still works with Yoko Taro on occasion, so it shouldn't be too difficult to get an enhanced PS5 version.
2 Infamous 1 and 2
PlayStation only seems interested in enhancing its PS4 games.
Infamous: Second Son was a big hit on the PS4, but Sucker Punch Productions has fully moved on to its new series, Ghost of Tsushima and Ghost of Yotei. That's great, but that means someone else on PlayStation needs to step up and get Infamous and Infamous 2 on PS5 natively. A collection of both games, remastered and enhanced, would be a huge improvement over dealing with the PS3 cloud streaming on PS5. It seems wrong that a beloved series by a beloved studio isn't playable just a bit over 15 years after release.
Infamous follows a super-powered Cole, who gets caught in a massive explosion in a fictionalized city based on New York. He gets electricity super-powers, which can be used in fast-paced action combat. If you have enjoyed any of the Marvel's Spider-Man games on PlayStation, Infamous feels like a less modern version of that combat, with fewer exciting movement abilities.

1 Yakuza: Dead Souls
An oddity in the series, in need of some modern polish

Source: Sega
Yakuza: Dead Souls is one of the many, many side games in the Yakuza series, like the most recent one, Like A Dragon: Pirate Yakuza In Hawaii. This is a non-canon story that takes place after the events of Yakuza 4. There is a zombie outbreak, requiring four characters, including the beloved Kazuma Kiryu and Goro Majima, to help the people of Kamarocho and find the source of the outbreak. Like A Dragon: Ishin was another spin-off that recently got remastered for modern platforms, so there is no reason to leave this one stuck on the PS3. It's not exactly a beloved entry in the series, but its unique focus on horror makes it stand out in the series, and it's got more great character moments with your favorite people. It mixes the usual beat-em-up combat with more third-person shooting. With most games in the series available on the PS5, the collection should be complete by bringing over Yakuza: Dead Souls.
PlayStation needs to get more PS3 games running on PS5
It's clear that there are too many PS3 games left on the old hardware that need to be enhanced for PS5. Not only is cloud streaming these games a half-solution, but considering the high number of Xbox and Xbox 360 games that Microsoft was able to get running on Xbox Series X|S, with many of them running better than they did originally, there is no excuse for PlayStation. Sure, it requires time and resources, but abandoning older games to older hardware is bad for the industry. Plus, PlayStation hasn't been releasing that many games for the PS5 anyway, so these enhanced versions could help fill out the lineup.

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