Really great stuff here!
Those Ability Capsules look like they'd be really useful for situations where an item or power-up is required to progress, so we don't need to fill the level with resets doors and such. It's especially nice how they can be used to give items like Bob-Ombs, Shells or Yoshies, so they're more than just power-up respawners.
It's very interesting how they don't give reserve items.
Also, that's a nice collection of SMB2U sprites! They seem very faithful to the original versions, and it's cool you've included some extra customization for them!
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