diff --git a/Gruntfile.js b/Gruntfile.js
new file mode 100644
index 0000000..0295c3f
--- /dev/null
+++ b/Gruntfile.js
@@ -0,0 +1,25 @@
+module.exports = function(grunt) {
+  grunt.initConfig({
+    babel: {
+      scripts: {
+        files: [{
+          expand: true,
+          cwd: 'src',
+          src: '**/*.js',
+          dest: 'build/'
+        }]
+      }
+    },
+    watch: {
+      scripts: {
+        files: ['src/**/*.js'],
+        tasks: ['babel']
+      }
+    }
+  });
+
+  grunt.loadNpmTasks('grunt-babel');
+  grunt.loadNpmTasks('grunt-contrib-watch');
+
+  grunt.registerTask('default', ['babel']);
+};
diff --git a/build/classes/interface.js b/build/classes/interface.js
new file mode 100644
index 0000000..bc745e7
--- /dev/null
+++ b/build/classes/interface.js
@@ -0,0 +1,90 @@
+'use strict';
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+var _ansi = require('ansi');
+
+var _ansi2 = _interopRequireDefault(_ansi);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var _process = process;
+var stdout = _process.stdout;
+var stdin = _process.stdin;
+
+var listeners = [];
+
+var prefix = '\u001b';
+var keys = {
+  right: prefix + '[C',
+  up: prefix + '[A',
+  left: prefix + '[D',
+  down: prefix + '[B',
+  exit: '\u0003',
+  space: ' '
+};
+
+var Interface = (function () {
+  function Interface() {
+    var output = arguments.length <= 0 || arguments[0] === undefined ? stdout : arguments[0];
+    var input = arguments.length <= 1 || arguments[1] === undefined ? stdin : arguments[1];
+
+    _classCallCheck(this, Interface);
+
+    this.output = output;
+    this.input = input;
+
+    this.input.setRawMode(true);
+    this.input.setEncoding('utf8');
+
+    this.cursor = (0, _ansi2.default)(this.output).hide();
+
+    this.columns = this.output.columns;
+    this.rows = this.output.rows;
+
+    this.input.addListener('data', function (data) {
+      var key = Object.keys(keys).find(function (value, i) {
+        return keys[value] === data;
+      });
+
+      if (key === 'exit') process.exit();
+
+      var match = listeners.filter(function (listener) {
+        return listener.key === key || listener.key === data;
+      });
+
+      match.forEach(function (listener) {
+        return listener.fn();
+      });
+    });
+  }
+
+  _createClass(Interface, [{
+    key: 'clear',
+    value: function clear() {
+      this.output.write('\u001b[2J\u001b[0;0H');
+    }
+  }, {
+    key: 'write',
+    value: function write() {
+      var _cursor;
+
+      (_cursor = this.cursor).write.apply(_cursor, arguments);
+    }
+  }, {
+    key: 'onKey',
+    value: function onKey(key, fn) {
+      listeners.push({ key: key, fn: fn });
+    }
+  }]);
+
+  return Interface;
+})();
+
+exports.default = Interface;
diff --git a/build/classes/unit.js b/build/classes/unit.js
new file mode 100644
index 0000000..2b31149
--- /dev/null
+++ b/build/classes/unit.js
@@ -0,0 +1,122 @@
+'use strict';
+
+var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var Unit = (function () {
+  function Unit(output) {
+    _classCallCheck(this, Unit);
+
+    this._health = 0;
+    this.dead = false;
+    this.output = output;
+
+    this.dieOnExit = false;
+  }
+
+  _createClass(Unit, [{
+    key: 'move',
+    value: function move(x, y) {
+      if (!x && !y) return this.move.apply(this, _toConsumableArray(this.speed()));
+      this.x += x;
+      this.y += y;
+    }
+  }, {
+    key: 'draw',
+    value: function draw() {
+      if (this.dead) return;
+
+      var x = this.x;
+      var y = this.y;
+      var shape = this.shape;
+
+      if (this.color && this.color[0] === '#') {
+        this.output.cursor.hex(this.color);
+      } else if (this.color) {
+        this.output.cursor[this.color]();
+      }
+      if (this.bold) this.output.cursor.bold();
+
+      this.output.cursor.goto(Math.round(x), Math.round(y));
+      this.output.write(shape);
+      this.output.cursor.reset();
+    }
+  }, {
+    key: 'go',
+    value: function go(x, y) {
+      this.x = x;
+      this.y = y;
+    }
+  }, {
+    key: 'speed',
+    value: function speed() {
+      var signs = [Math.random() > 0.5 ? -1 : 1, Math.random() > 0.5 ? -1 : 1];
+      return [Math.random() * signs[0], Math.random() * signs[1]];
+    }
+  }, {
+    key: 'collides',
+    value: function collides(target) {
+      var _this = this;
+
+      if (Array.isArray(target)) {
+        return target.find(function (t) {
+          return _this.collides(t);
+        });
+      }
+
+      var targetX = Math.round(target.x);
+      var targetY = Math.round(target.y);
+      var x = Math.round(this.x);
+      var y = Math.round(this.y);
+
+      return x === targetX && y == targetY;
+    }
+  }, {
+    key: 'health',
+    set: function set(value) {
+      this._health = Math.min(0, value);
+
+      if (this.health === 0) {
+        this.dead = true;
+      }
+    },
+    get: function get() {
+      return this._health;
+    }
+  }, {
+    key: 'x',
+    set: function set(value) {
+      this._x = value;
+
+      if (this.dieOnExit && this._x > this.output.columns) {
+        this.dead = true;
+      }
+    },
+    get: function get() {
+      return this._x;
+    }
+  }, {
+    key: 'y',
+    set: function set(value) {
+      this._y = value;
+
+      if (this.dieOnExit && this._y > this.output.rows) {
+        this.dead = true;
+      }
+    },
+    get: function get() {
+      return this._y;
+    }
+  }]);
+
+  return Unit;
+})();
+
+exports.default = Unit;
diff --git a/build/spacecraft.js b/build/spacecraft.js
new file mode 100644
index 0000000..ffe1f16
--- /dev/null
+++ b/build/spacecraft.js
@@ -0,0 +1,111 @@
+'use strict';
+
+var _unit = require('./classes/unit');
+
+var _unit2 = _interopRequireDefault(_unit);
+
+var _interface = require('./classes/interface');
+
+var _interface2 = _interopRequireDefault(_interface);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+var FRAME = 20;
+var ENEMY_SPAWN_RATE = 400;
+
+var ui = new _interface2.default();
+
+var player = new _unit2.default(ui);
+player.go(1, ui.output.rows / 2);
+player.shape = '=>';
+player.color = '#77d6ff';
+player.bold = true;
+
+var explosion = new _unit2.default(ui);
+explosion.dead = true;
+
+var missles = [];
+var enemies = [];
+var score = 0;
+setInterval(function () {
+  ui.clear();
+
+  player.draw();
+
+  missles.forEach(function (missle, i) {
+    missle.move(1, 0);
+    missle.draw();
+
+    var enemy = missle.collides(enemies);
+    if (enemy) {
+      enemy.killed = 1;
+      enemy.color = 'red';
+      enemy.shape = '*';
+      missle.dead = true;
+
+      score++;
+    }
+
+    if (missle.dead) {
+      missles.splice(i, 1);
+    }
+  });
+
+  enemies.forEach(function (enemy, i) {
+    // move with speed
+    enemy.move();
+    enemy.draw();
+
+    if (enemy.dead) {
+      enemies.splice(i, 1);
+    }
+
+    if (enemy.killed == 3) enemy.dead = true;
+    if (enemy.killed < 3) enemy.killed++;
+  });
+
+  ui.cursor.goto(0, 0).yellow().write('Score: ' + score);
+  ui.cursor.reset();
+}, FRAME);
+
+ui.onKey('right', function () {
+  player.move(1, 0);
+});
+ui.onKey('down', function () {
+  player.move(0, 1);
+});
+ui.onKey('up', function () {
+  player.move(0, -1);
+});
+ui.onKey('left', function () {
+  player.move(-1, 0);
+});
+ui.onKey('space', function () {
+  var missle = new _unit2.default(ui);
+  missle.go(player.x, player.y);
+  missle.shape = '+';
+  missle.dieOnExit = true;
+
+  missles.push(missle);
+});
+
+setInterval(function () {
+  if (enemies.length > 5) return;
+
+  var enemy = new _unit2.default(ui);
+  enemy.go(Math.random() * ui.output.columns, 0);
+  enemy.shape = 'o';
+  enemy.color = '#f7c71e';
+  enemy.dieOnExit = true;
+
+  enemy.speed = function () {
+    return [Math.random() > 0.9 ? 0.4 : 0, 0.06];
+  };
+
+  enemies.push(enemy);
+}, 1000);
+
+process.on('exit', function () {
+  ui.cursor.horizontalAbsolute(0).eraseLine();
+  ui.cursor.show();
+});
diff --git a/index.js b/index.js
index f91c8a4..8d3d36f 100755
--- a/index.js
+++ b/index.js
@@ -11,6 +11,5 @@ if (!game) {
 }
 
 require('babel-polyfill');
-require('babel-core/register');
 
-require(__dirname + '/' + game);
+require(__dirname + '/build/' + game);
diff --git a/package.json b/package.json
index e870cb2..a2f6627 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "node-games",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "Simple node console games",
   "main": "index.js",
   "scripts": {
@@ -26,5 +26,10 @@
     "babel-core": "6.3.17",
     "babel-polyfill": "6.3.14",
     "babel-preset-es2015": "6.3.13"
+  },
+  "devDependencies": {
+    "grunt": "0.4.5",
+    "grunt-babel": "6.0.0",
+    "grunt-contrib-watch": "0.6.1"
   }
 }
diff --git a/classes/interface.js b/src/classes/interface.js
similarity index 100%
rename from classes/interface.js
rename to src/classes/interface.js
diff --git a/classes/unit.js b/src/classes/unit.js
similarity index 100%
rename from classes/unit.js
rename to src/classes/unit.js
diff --git a/spacecraft.js b/src/spacecraft.js
similarity index 100%
rename from spacecraft.js
rename to src/spacecraft.js