Best weapon design/strength/efficiency/range/rate of attack/Blah blah blah. Vampire Killer doesn't count because of redundancy Must be from: Symphony Of the Night Dawn/Aria Of Sorrow Harmony of Dissonance Circle Of The Moon Order Of Ecclesia Portrait of Ruin Curse Of Darkness (PS2) Lament Of Innocence (PS2) I've always loved the Claimh Solais tied with the Hrunting from the ... Of Sorrow series.
Metroidvania refers to games that are like that of Metroid, or Castlevania, it doesn't refer to only Castlevania.
But it's commonly referred to games that take on the "Metroid" style gameplay. Like Symphony of the Night.
Crissaegrim or Valmanway as it's known in the games after Symphony of the Night by far. Not the strongest, but it hits so fast it doesn't matter. Easily one of the most overpowered weapons ever.
Hmmm.. very interesting choices going on here. The Photon Rifle, previously stated by groh is a good choice too. Post Merge: [time]1276028819[/time] Now-a-days you don't see anything like Symphony of the Night anymore excluding the future DS releases, just think of that awkward "Lords Of Shadow" from upcoming release, now doesn't that look like a fun large mono-castle, Not really. My point is that, games just don't use that Metroid/Super Metroid feel anymore not even the "Other M" (maybe).
Batman: Arkham Asylum was a metroidvania game (it's linear but you can almost go to every area from the get go, but you can't progress in any area unless you have x power-up, like Metroid).