I forked and downloaded the repo, ran npm install, then npm start. I can see the title screen and that works, but once the game starts it crashes in the PlayState update() when it tries to access body.plus.contactNormal.length(). However, I changed the code to avoid using the normals and was able to get the demo to actually display the game map. Obviously the game didn't function without movement and whatnot, but all of the tiles were animated, etc.

I'm running NPM 3.10.10 with your most up to date version. Previously had version 0.9.1 or so and the issue was also present there.
From package.json:

"dependencies": {
    "lodash": "^4.17.4",
    "phaser-ce": "^2.9.1",
    "phaser-tilemap-plus": "^0.10.2",
    "poly-decomp": "^0.2.1"
  },

Here's the contents of body.plus when it errors out on Cannot access property length of undefined on the attempted call to body.plus.contactNormal.length():

Contents of body.plus

  "shape": {
    "vertices": [
      {
        "x": 10,
        "y": -10
      },
      ...
      {
        "x": 10,
        "y": 10
      }
    ],
    "aabb": {
      "left": -10,
      "right": 10,
      "top": -19.84807753012208,
      "bottom": 19.84807753012208
    },
    "edges": [
      {
        "x": -0.6030737921409148,
        "y": -3.420201433256686
      },
      ...
      {
        "x": 0,
        "y": -20
      }
    ],
    "normals": [
      {
        "x": 0.9848077530122081,
        "y": -0.17364817766693003
      },
     ...
      {
        "x": 1,
        "y": 0
      }
    ],
    "count": 20,
    "centre": {
      "x": 8.881784197001253e-17,
      "y": 5.329070518200751e-16
    }
  }
}```

I cloned the repository, installed all the packages, but when I run it, just after hitting the space bar I get the errors: "Cannot read property 'playerStartX ' of undefined at PlayState.create (PlayState.js?5afc:74)" and "Cannot read property 'left' of null at PlayState.update (PlayState.js?5afc:134)".