diff --git a/src/fastfiz_env/make.py b/src/fastfiz_env/make.py
index 9b13b4e..14d315b 100644
--- a/src/fastfiz_env/make.py
+++ b/src/fastfiz_env/make.py
@@ -1,3 +1,4 @@
+from typing import Optional
 from gymnasium.envs.registration import EnvSpec
 import gymnasium as gym
 
@@ -39,7 +40,11 @@ def make(
 
 
 def make_wrapped_env(
-    env_id: str, num_balls: int, max_episode_steps: int, reward_function: RewardFunction
+    env_id: str,
+    num_balls: int,
+    max_episode_steps: int,
+    reward_function: RewardFunction,
+    **kwargs,
 ):
     """
     Create an instance of the specified environment with the FastFizActionWrapper.
@@ -50,6 +55,7 @@ def make_wrapped_env(
         num_balls=num_balls,
         max_episode_steps=max_episode_steps,
         disable_env_checker=False,
+        **kwargs,
     )
     env = FastFizActionWrapper(env, action_space_id=ActionSpaces.NO_OFFSET_3D)
     return env
@@ -60,6 +66,7 @@ def make_callable_wrapped_env(
     num_balls: int,
     max_episode_steps: int,
     reward_function: RewardFunction,
+    **kwargs,
 ):
     """
     Create a callable function that returns an instance of the specified environment with the FastFizActionWrapper.
@@ -67,6 +74,8 @@ def make_callable_wrapped_env(
     """
 
     def _init() -> gym.Env:
-        return make_wrapped_env(env_id, num_balls, max_episode_steps, reward_function)
+        return make_wrapped_env(
+            env_id, num_balls, max_episode_steps, reward_function, **kwargs
+        )
 
     return _init
diff --git a/src/optimize.py b/src/optimize.py
index 222728b..0de08dc 100644
--- a/src/optimize.py
+++ b/src/optimize.py
@@ -135,13 +135,14 @@ def objective(
     n_timesteps: int,
     start_time: str,
     no_logs: bool,
+    env_kwargs: dict,
 ) -> float:
     kwargs = sample_ppo_params(trial)
     N_ENVS = 4
 
     env = make_vec_env(
         make_callable_wrapped_env(
-            env_id, num_balls, max_episode_steps, reward_function
+            env_id, num_balls, max_episode_steps, reward_function, **env_kwargs
         ),
         n_envs=N_ENVS,
     )
@@ -206,6 +207,28 @@ def save_trial(trial: optuna.trial.FrozenTrial, path: str) -> None:
         )
 
 
+class StoreDict(argparse.Action):
+    """
+    Custom argparse action for storing dict.
+
+    In: args1:0.0 args2:"dict(a=1)"
+    Out: {'args1': 0.0, arg2: dict(a=1)}
+    """
+
+    def __init__(self, option_strings, dest, nargs=None, **kwargs):
+        self._nargs = nargs
+        super().__init__(option_strings, dest, nargs=nargs, **kwargs)
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        arg_dict = {}
+        for arguments in values:  # type: ignore
+            key = arguments.split(":")[0]
+            value = ":".join(arguments.split(":")[1:])
+            # Evaluate the string as python code
+            arg_dict[key] = eval(value)
+        setattr(namespace, self.dest, arg_dict)
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Description of your program")
     parser.add_argument("--n_trials", type=int, default=20, help="Number of trials")
@@ -249,6 +272,15 @@ def save_trial(trial: optuna.trial.FrozenTrial, path: str) -> None:
         "--no-logs", action="store_true", help="Disable Tensorboard logging"
     )
 
+    parser.add_argument(
+        "--env-options",
+        type=str,
+        nargs="+",
+        action=StoreDict,
+        help="Optional keyword argument to pass to the env constructor",
+        default={},
+    )
+
     args = parser.parse_args()
 
     # Set pytorch num threads to 1 for faster training.
@@ -265,6 +297,8 @@ def save_trial(trial: optuna.trial.FrozenTrial, path: str) -> None:
 
     reward_function = DefaultReward if args.reward == "DefaultReward" else WinningReward
 
+    env_kwargs = {"options": args.env_options}
+
     def obj_fn(trial):
         return objective(
             trial,
@@ -277,6 +311,7 @@ def obj_fn(trial):
             args.n_timesteps,
             start_time,
             args.no_logs,
+            env_kwargs,
         )
 
     try: