package.json

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "dependencies": {
    "riot": "^3.4.2"
  },
  "devDependencies": {
    "coffee-script": "^1.12.5",
    "pug": "^2.0.0-rc.1",
    "stylus": "^0.54.5"
  },
  "scripts": {
    "start": "riot --template pug --type coffee --style stylus test.tag test.js"
  },
  "author": "Gianluca Guarini <gianluca.guarini@gmail.com> (http://gianlucaguarini.com)",
  "license": "MIT"
}

test.tag

home
  h1 some title here
  p hello world

  script(type="coffee").
    # your coffee script here
    console.log "Starting a Riot!"

  style.
    /* your css here */
    .project{
      background-color: #000;
    }


  style(type="stylus")
    // your stylus here

I think style(type="stylus") should be style(type="stylus"). (note trailing dot).