- Progression of gameplay based on obtaining items or upgrades that allow for new areas and/or story to be reached
- Has an open ended or free roaming world
- Focus on either puzzle solving through platforming or a mixture of additional genres with a focus on platforming (such as Castlevania with RPG elements)
It's been a while since i've played AC and Infamous.
but i'm a little confused how Assassin's Creed and Infamous fit into some of these categories as far as i know none of the Items you gather in these game opens up new areas in the same way that super missiles or space jump boots helps you reach new areas in metroid games.
As for Batman Arkham Asylum, it is very metroid inspired but the game has like no platforming at all, or perhaps i classify platforming differently.
I think your criterias for what a metroid game is are slightly off.
another game, Muramasa is really really and i mean really really metroid-lite, there are no puzzles in that game and i wouldnt call it a freeroaming/open world type of game, i wouldnt even call it a platforming game
