diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8dcbfb0..207f3fd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -92,3 +92,4 @@ jobs:
       - uses: jamescurtin/isort-action@master
         with:
             requirementsFiles: "requirements.txt"
+            configuration: "--check-only --diff --trailing-comma --multi-line=3"
diff --git a/pythonium/game_modes/__init__.py b/pythonium/game_modes/__init__.py
index 98c209d..35a82c2 100644
--- a/pythonium/game_modes/__init__.py
+++ b/pythonium/game_modes/__init__.py
@@ -1,7 +1,9 @@
+from pythonium.game_modes.asteroid.game_mode import AsteroidsMode
 from pythonium.game_modes.classic_mode import ClassicMode
 from pythonium.game_modes.sandbox_mode import SandboxGameMode
 
 GAME_MODES = {
     'classic': ClassicMode,
     'sandbox': SandboxGameMode,
+    'asteroid': AsteroidsMode,
 }
diff --git a/pythonium/game_modes/asteroid/__init__.py b/pythonium/game_modes/asteroid/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pythonium/game_modes/asteroid/game_mode.py b/pythonium/game_modes/asteroid/game_mode.py
new file mode 100644
index 0000000..2d5b96c
--- /dev/null
+++ b/pythonium/game_modes/asteroid/game_mode.py
@@ -0,0 +1,73 @@
+from pythonium import ShipType, Transfer, Ship, Galaxy
+from pythonium.core import Position
+from pythonium.game_modes.classic_mode import ClassicMode
+from pythonium.game_modes.asteroid.rules import get_asteroids, DestroyAsteroidsRule, DestroyShipRule, \
+    CreateAsteroidsRule, MoveAsteroidsRule
+from pythonium.rules.ship import ShipMoveRule
+
+SHIP_SPEED = 5
+SHIP_TYPE = ShipType(
+    name='traveler',
+    speed=SHIP_SPEED,
+    cost=Transfer(),
+    max_cargo=0,
+    max_mc=0,
+    attack=0,
+)
+
+
+class AsteroidsMode(ClassicMode):
+    ship_speed = SHIP_SPEED
+    ship_type = SHIP_TYPE
+    rules = [
+        DestroyAsteroidsRule,
+        CreateAsteroidsRule,
+        ShipMoveRule,
+        MoveAsteroidsRule,
+        DestroyShipRule,
+    ]
+
+    def __init__(self, max_turn=300, *args, **kwargs):
+        super().__init__(
+            max_turn=max_turn,
+            *args,
+            **kwargs
+        )
+
+    def build_galaxy(self, name, players):
+        ships = []
+        ship_position = (self.map_size[0] / 2, self.map_size[1])
+        for player in players:
+            ship = Ship(
+                player=player.name,
+                type=self.ship_type,
+                position=Position(ship_position),
+                max_cargo=self.ship_type.max_cargo,
+                max_mc=self.ship_type.max_mc,
+                attack=self.ship_type.attack,
+                speed=self.ship_type.speed,
+            )
+            ships.append(ship)
+        return Galaxy(name=name, size=self.map_size, things=ships)
+
+    def has_ended(self, galaxy, t):
+        if t == self.max_turn:
+            return True
+
+        if not galaxy.known_races:
+            return True
+
+        return False
+
+    def galaxy_for_player(self, galaxy, player):
+        return galaxy
+
+    def get_context(self, galaxy, players, turn):
+        asteroids = get_asteroids(galaxy)
+        return {
+            'asteroids': len(asteroids),
+            'score': [
+                {'ships': 1}
+                for _ in galaxy.known_races
+            ]
+        }
diff --git a/pythonium/game_modes/asteroid/player.py b/pythonium/game_modes/asteroid/player.py
new file mode 100644
index 0000000..f0ea38a
--- /dev/null
+++ b/pythonium/game_modes/asteroid/player.py
@@ -0,0 +1,18 @@
+from pythonium import Galaxy
+from pythonium.core import Position
+from pythonium.player import AbstractPlayer
+
+
+class Player(AbstractPlayer):
+    name = 'explorer'
+
+    def next_turn(self, galaxy: Galaxy, context: dict) -> Galaxy:
+        ships = galaxy.get_player_ships(self.name)
+
+        for ship in ships:
+            ship.target = Position((
+                ship.position[0],
+                0,
+            ))
+
+        return galaxy
diff --git a/pythonium/game_modes/asteroid/rules.py b/pythonium/game_modes/asteroid/rules.py
new file mode 100644
index 0000000..22a5f7a
--- /dev/null
+++ b/pythonium/game_modes/asteroid/rules.py
@@ -0,0 +1,76 @@
+import random
+
+from pythonium.core import Position
+from pythonium.game_modes.asteroid.things import Asteroid
+from pythonium.rules.core import GalaxyRule
+
+
+def get_asteroids(galaxy):
+    return [a for a in galaxy.things if isinstance(a, Asteroid)]
+
+
+class DestroyAsteroidsRule(GalaxyRule):
+
+    def execute(self) -> None:
+        to_remove = []
+        asteroids = get_asteroids(self.galaxy)
+        for asteroid in asteroids:
+            if asteroid.position[0] > self.galaxy.size[0]:
+                to_remove.append(asteroid)
+        self.galaxy.things = [
+            thing for thing in self.galaxy.things
+            if thing not in to_remove
+        ]
+
+
+class DestroyShipRule(GalaxyRule):
+
+    def execute(self) -> None:
+        asteroids = get_asteroids(self.galaxy)
+        to_destroy = []
+        for ship in self.galaxy.ships:
+            nearby_asteroids = [
+                a for a in asteroids
+                if self.galaxy.compute_distance(
+                    ship.position,
+                    a.position,
+                ) < 20
+            ]
+            if nearby_asteroids:
+                to_destroy.append(ship)
+        self.galaxy.things = [
+            thing for thing in self.galaxy.things
+            if thing not in to_destroy
+        ]
+
+
+class CreateAsteroidsRule(GalaxyRule):
+    new_asteroid_period = 5
+
+    def execute(self) -> None:
+        asteroids = get_asteroids(self.galaxy)
+        nominal_asteroids = int(self.galaxy.turn / self.new_asteroid_period)
+        real_asteroids = len(asteroids)
+        pending_asteroids = nominal_asteroids - real_asteroids
+        for _ in range(pending_asteroids):
+            self.galaxy.things.append(
+                Asteroid(position=self._get_random_position())
+            )
+
+    def _get_random_position(self) -> Position:
+        return Position((
+            self.galaxy.size[0],
+            int(random.random() * self.galaxy.size[1])
+        ))
+
+
+class MoveAsteroidsRule(GalaxyRule):
+
+    def execute(self) -> None:
+        asteroids = get_asteroids(self.galaxy)
+        for asteroid in asteroids:
+            new_position = Position((
+                asteroid.position[0] - 10,
+                asteroid.position[1]
+            ))
+            asteroid.position = new_position
diff --git a/pythonium/game_modes/asteroid/things.py b/pythonium/game_modes/asteroid/things.py
new file mode 100644
index 0000000..b224554
--- /dev/null
+++ b/pythonium/game_modes/asteroid/things.py
@@ -0,0 +1,18 @@
+import math
+import random
+from typing import Tuple
+
+import attr
+
+from pythonium.core import StellarThing
+
+
+def random_direction():
+    angle = random.random() * math.pi
+    return math.cos(angle), math.sin(angle)
+
+
+@attr.s(auto_attribs=True, repr=False)
+class Asteroid(StellarThing):
+    thing_type = "planet"
+    direction: Tuple[float, float] = attr.ib(factory=random_direction)
diff --git a/pythonium/game_modes/classic_mode.py b/pythonium/game_modes/classic_mode.py
index 5324463..dc2f13a 100644
--- a/pythonium/game_modes/classic_mode.py
+++ b/pythonium/game_modes/classic_mode.py
@@ -44,7 +44,16 @@
 
 class ClassicMode(GameMode):
 
-    # Define los atributos de las ships que se pueden construir.
+    rules = [
+        ShipTransferRule,
+        PlanetBuildMinesRule,
+        PlanetSetTaxesRule,
+        ShipMoveRule,
+        ResolveShipsConflicts,
+        ResolvePlanetsConflicts,
+        PlanetBuildShipRule,
+        ProduceResources,
+    ]
 
     def __init__(
         self,
@@ -89,16 +98,6 @@ def __init__(
         self.max_turn = max_turn
         self.max_ships = max_ships
         self.winner = None
-        self.rules = [
-            ShipTransferRule,
-            PlanetBuildMinesRule,
-            PlanetSetTaxesRule,
-            ShipMoveRule,
-            ResolveShipsConflicts,
-            ResolvePlanetsConflicts,
-            PlanetBuildShipRule,
-            ProduceResources,
-        ]
 
     def build_galaxy(self, name, players):
         """