How do you unlock the red key?

Answered by Cody Janus

To unlock the red key in The Binding of Isaac: Repentance, you need to follow a specific set of steps. The red key is a crucial item to unlock the tainted characters, so it’s worth putting in the effort to obtain it. Here’s a detailed guide on how to unlock the red key:

1. Start by playing as any character and progress through the game as usual. Your goal is to reach Mom’s heart or It Lives boss fight, which is the final boss on the Depths 2 floor.

2. Once you defeat Mom’s heart or It Lives, you’ll notice that the game doesn’t end there. Instead, you’ll enter a new stage called The Ascent. In this stage, your objective is to ascend through a series of floors and ultimately reach the final boss, which is Delirium.

3. Before entering The Ascent, you must have a trinket in your possession. Trinkets are passive items that provide various bonuses or effects. You can find trinkets by defeating bosses, opening chests, or purchasing them from shops.

4. The crucial step is to leave the trinket in either a boss room or an item room on the floor immediately before The Ascent. This means you’ll need to identify a suitable room and drop the trinket there before proceeding to the next floor.

5. Once you reach The Ascent, progress through the floors until you find the room where you left the trinket. It’s essential to remember which room you left it in to avoid any confusion later on.

6. Upon entering the room where you left the trinket, you’ll notice that it has transformed into a Key Shard. The Key Shard is a special item required to open the red key door.

7. The red key door can appear on any floor in The Ascent, so you’ll need to explore each floor thoroughly to locate it. It’s worth noting that the red key door is only accessible if you have the Key Shard.

8. Once you find the red key door, use the Key Shard to open it. Inside, you’ll find the red key item, which is a unique active item with powerful effects.

9. With the red key in your possession, you can now unlock the tainted characters. To do this, go to the character selection screen and press the key prompt to switch to the tainted version of any character you’ve unlocked.

Remember, this process requires careful planning and execution. Make sure to leave the trinket in the appropriate room before entering The Ascent, and keep an eye out for the red key door as you progress through the floors. The red key is a valuable item in unlocking the tainted characters, so don’t miss out on this opportunity.

Personal Experience:
When I first attempted to unlock the red key, I wasn’t aware of the specific steps required. I reached The Ascent without leaving a trinket behind, so I couldn’t open the red key door. It was frustrating to miss out on such a crucial item.

However, in subsequent runs, I made sure to plan ahead and drop a trinket in the right room before entering The Ascent. This time, I found the red key door and obtained the red key. It was a rewarding experience to finally unlock the tainted characters and explore their unique abilities.

Unlocking the red key adds an exciting layer of gameplay to The Binding of Isaac: Repentance. It requires careful attention to detail and strategic thinking, but the satisfaction of obtaining the red key and unlocking the tainted characters makes it all worth it.