Unblocked [upd] | Deepest Sword

It sounds like you're referring to — an indie physics-based puzzle game where you control a dragon trying to reach a treasure by extending your sword to cross gaps. The phrase "unblocked" typically means playing it on a school or work network where game sites are restricted, and "solid feature" might refer to a key game mechanic (like the sword extension physics) or a request for a stable, unblocked version.