I mentioned in my last status update that I was considering making "a simple SMW hack with SMB1-style level progression and vanilla aesthetics." This is it. Super Mario Bros: Vanilla Islands is built using mostly vanilla graphics as a foundation. This doesn't mean that they haven't been edited, sometimes heavily so, to suit my purposes. This hack has 8 themed worlds, each with 3 normal levels and a castle (This is what I meant by SMB1-style level progression).
SCREENSHOTS
SCREENSHOTS