Don't say this is impossible, because there is a secret way to win. Hints below: but be warned, they may take the satisfaction in finding out the answer. Anybody who posts a hint may have his or her comment deleted. Hints: If you want to complete the game yourself, then don't look at these. It is almost always more satisfying to do things yourself than to look at a hint. Last Chance!!! Okay, I won't tell you the answer straight up, but here are hints: First Hint: Think outside the box - spamming the keys will not help, no matter what. Small hint: The answer to get the diamond is VERY different from the original project. Medium hint: you cannot brute-force the place where you place the answer Large hint: No matter what, there is no way to get the diamond BY TYPING IN ANSWERS Final, Massive Hints: Are you absolutely sure? Okay, fine. The guard is hiding something very important. No matter what answer you choose, you will never get the diamond. It has to do with the guard himself. What can you do to get him out of the way? The reward is large, the stakes are high. Can you get the gold diamond?
I could have done this myself, but I was too lazy to do it from scratch. So I remixed scar-2010's project instead. Clicking the "See Inside" button may cause lag, while pressing the heart or star button underneath the project window will reduce lag. Your actual reward if you can beat the game: a gold diamond! Just kidding on the heart and star button part :)
