Nintendo Games

ALL Switch 1 games are compatable with Switch 2, except for Nintendo Labo Toy-Con 04: VR Kit. For those unaware, this requires you to put your switch into a cardboard compartment, and the Switch 2 is bigger (and thus cannot fit inside it). It's not even a gameplay problem, it's literally a size problem which is absolutely hilarious to me.

However, some games will require Switch 1 joycon to play. These are games that either use a physical accessory or the IR camera. (They mention 1-2 Switch in this list too, but the wording seems to imply it will actually work with Joycon 2, but with one game being worse). These are: Ring Fit Adventure, 1-2-Switch, Everybody 1-2-Switch, Game Builder Garage, Nintendo Switch Sports, WarioWare: Move It!, and the other three Labos.

Third Party Games

Because the Switch 2 is on completely different hardware, games may not be fully compatable. This is similar to the Steam Deck's "Verified" thing, but it will be less extreme. Of the gmaes they have considered:

• ~20% of games had no obvious compatability issues when testing
• ~78% of games were able to be started without issue, but they are still doing further ongoing testing (there's over 15,000 games to check!)
• ~1% of titles are listed as "playable, with issues in certain parts of the game"
• <1% of titles are listed as "Issues were found during start up"

They have the list of titles that had issues (that they've tested so far) and plan to continuously update it. Additionally, these are all issues that need to be fixed by the original developers! So they'll need to update their games if the issue is severe enough, but it seems likely that most will only have minor problems, or issues with the FPS being higher.

Thankfully it's just what I predicted it'd be. Source: https://www.nintendo.com/us/gaming-systems/switch-2/transfer-guide/compatible-games/