diff --git a/main.py b/main.py
index fafc485..1f66175 100644
--- a/main.py
+++ b/main.py
@@ -1,5 +1,6 @@
 import argparse
 import random
+import sys
 from datetime import date, datetime
 from time import sleep
 
@@ -219,6 +220,10 @@ def get_prediction(
         return prediction_output
 
 
+def check_game_name(game: str) -> bool:
+    return game in GAME_INFO
+
+
 def main():
     parser = argparse.ArgumentParser(description="A lottery prediction tool.")
     subparsers = parser.add_subparsers(dest="command", required=True)
@@ -258,8 +263,9 @@ def main():
     ticket_parser.add_argument(
         "--game",
         type=str,
+        choices=[game for game in GAME_INFO.keys()],
         required=True,
-        help="The game to predict the next result for [MegaMillions, Powerball]",
+        help="The game to predict the next result for",
     )
 
     predict_parser = subparsers.add_parser(
@@ -269,8 +275,9 @@ def main():
     predict_parser.add_argument(
         "--game",
         type=str,
+        choices=[game for game in GAME_INFO.keys()],
         required=True,
-        help="The game to predict the next result for [MegaMillions, Powerball]",
+        help="The game to predict the next result for",
     )
     predict_parser.add_argument(
         "--window-size",
@@ -289,6 +296,9 @@ def main():
     args = parser.parse_args()
     match args.command:
         case "generate-ticket":
+            if not check_game_name(args.game):
+                print(f"{args.game} is not a valid game name.")
+                sys.exit()
             main_balls, game_ball = ticket.generate_random_ticket(
                 max_main=GAME_INFO[args.game]['max_main_ball'],
                 max_game=GAME_INFO[args.game]['max_game_ball'],
@@ -317,6 +327,9 @@ def main():
         case "update":
             update_games(dry_run=args.dryrun)
         case "predict":
+            if not check_game_name(args.game):
+                print(f"{args.game} is not a valid game name.")
+                sys.exit()
             if args.test:
                 recent, prediction = get_prediction(
                     game=args.game,