On-chain games? I don't want to feel like I'm in a laggy casino, I just want to blast zombies with a rocket launcher and I can already do that perfectly fine.
Uncensorable Github? Yeah, it's called "git".
Decentralized DNS and Postgres? Yeah, it's called "DNS" and "Postgres" respectively.
Web3 twitter?
> The winning Web3 Twitter will ultimately offer the features we have been eager to see: data truly owned by users themselves, uncontrolled by one entity or even one man, multiple clients permissionlessly built, multiple options of curation algorithms that users can choose from.
Congratulations you just described Mastodon and ActivityPub. No blockchain required (though it does depend on those boring web2 technologies like HTTPS and DNS).