In the original Mortal Kombat from 1992, Reptile is indeed a hidden character. However, unfortunately, he is not unlockable as a playable character. Reptile only makes a special appearance as a secret boss in the game. Nonetheless, I'll tell you how to face Reptile as a secret boss. 1. **Choose either Pit stage:** Reptile will only appear on this stage. 2. **Double Flawless Victory:** You need to win both rounds of the match without taking any damage. 3. **No Block:** Don’t use the block button during the entire match. 4. **The Silhouette:** Wait for a silhouette to glide past the moon on the Pit stage. This happens randomly, so there's no fixed method to trigger it. 5. **Finish with a Fatality(IL):** End the match with a Fatality (this doesn't apply to the Super Nintendo version). Meeting each of these conditions in a single-player match will trigger a fight with Reptile. As a tip: Use the "Endurance" matches in Solo Player Mode (It's the 6th stage). These matches allow you to enact a fatality after defeating the second opponent (which requires the first character to jump in as soon as you beat the first one), this gives you two chances for a 'double flawless victory' in one match which will make triggering Reptile's encounter a bit easier. Note: In later versions of Mortal Kombat, Reptile does become a playable character. I hope this helps even though Reptile can't be unlocked as a playable character in this game. Enjoy playing Mortal Kombat!