HT Games
* You need to beat the casino. Rescuing the sprites is only one step. You must also complete the casino's "main quest" by defeating the final boss, usually a giant monster. Once you do that, the casino will officially open, and you'll be able to play the matching card game.
* You're not playing at the right time. The matching card game is only available during certain hours. Check the casino's schedule to see when it's open. It's usually available after a specific time in the evening.
* You have the wrong item. While some Harvest Moon games allow you to use a special item to unlock the casino, the DS version doesn't require that. It's all about beating the casino boss.
* There is a glitch. It's rare, but glitches can prevent certain events from triggering in Harvest Moon games. Try restarting your game, saving and reloading, or even trying a different save file.
Here are some tips to try:
1. Double-check the casino's opening hours. Look for a notice board inside the casino or talk to the casino manager.
2. Ensure you've defeated the casino boss. If you haven't, it's the main reason you can't play.
3. Try restarting your game. A fresh start can sometimes fix glitches.
4. Check online for specific instructions. The Harvest Moon DS community might have more specific advice on unlocking the card game.
Let me know if you have any other questions!