Welcome to the Depth, a scenario that focuses on exploring huge areas. This guide is about collecting enough sun and stone keys to unlock all of the doors in the last area. In order to complete Creepy Castle, this needs to be done both in Depth and Free Depth. Finding all of the neccessary keys is no easy task.

In this scenario there are 2 types of keys:






You do not have to find every stone key since some of them are acquired after using one to unlock a door to an optional area. Thus following this guide can help you collect enough keys, though it requires avoiding one of the stone key doors in the lava level.

Note
This guide is sectioned based on the level. Each section lists all of the keys you can get at this point, not all of the keys in the level. For example, there is a sun key in the first level that you cannot get until you get the second level's item, thus directions for getting this key will be in the second level section.

This area does not have save points. You must find a stone key here to progress to the first level.




Climb down from the left side and unlock a brown door. You can fall through a gap to the first level.

The first level with a save point is a large cavern. Before you enter the second area, you can find eleven stone keys and three sun keys.

I apologize in advance that for the cavern level, the map shown for each screenshot does not follow the exact order of the guide at the moment. Each screenshot was taken in Free Depth while each map was taken in Depth, so I took slightly different routes then. In general the keys in this level can be accessed in any order.


The first five keys listed here can be easily accessed in the upper area without falling off a ledge.











The next three keys listed are accessible in the bottom-left area, blocked by three salamanders in a row. The area is also next to a new save point.











The last keys you can get in this area is in the center area accessible by unlocking a brown door and falling off a ledge. The two main exits are falling off the ledge to the center save point near sun key #2 and a green door you can open from here.









After following this you should have found all the keys you can in this area. Head to the second area, which is blocked off by a brown door and two yellow doors. You should then have three stone keys and one sun key left before entering the next area.

There are two more keys you can get later in this area. You can get the sun key with the second area's item (see the Waterfall Cave section) and the stone key with the fourth area's item (see the Inverted Pyramid section).

In this level, you can get two to four stone keys (depending on which path you take) and three sun keys. All of them can be retrieved without this level's item. There is also a sun key from the previous level you can get with this level's item.


The first key here is in the area near the first save point you can access.



The next two stone keys listed are completely optional. They are located in the lower-left area of the level.

There are two areas on the bottom-left of the level that are each blocked by a brown door. They can be skipped since they each only yield an alternative entrance to the level's item. Keep in mind that you have to solve the bottom-right area's puzzle to open up the entrance to the next level and doing so unlocks a path to the item anyway.

If you happen to unlock either of the doors you can find a stone key in each area.

Upper Brown Door

Lower Brown Door


This sun key is located in the lower-right area of the level.



Note
After collecting this key, use this opportunity to get this level's item if you haven't already done so. This is required to get the sun key from in the previous level. This sun key will be covered by the end of this section.


The next three keys are found in the left area right below the upper save point. You will fall down a ledge to enter it and cannot leave it until you defeat the area's boss.







This level's item allows you to get the sun key in the previous level. Go back to the area near the second sun key (see Caverns section) and use the item to reach the area's boss.


Go back to the second level and find its exit to the right. After unlocking two yellow doors you should have three sun keys and three stone keys remaining before entering the third level.

This level is an interesting case because there are a few optional stone keys in the building to the right. Since these keys are easy to find once you unlock one of the building's brown doors, this guide will only cover the required stone key there.

Besides the optional stone keys, you can find five stone keys and three sun keys in this level. None of them require this level's item.

*Warning*
This guide skips unlocking a certain brown door on one of the center floors leading to the structure on the right with the gray gates.
After getting the stone keys #16 and #17 you can reach the building by the top path. I believe you can go via the middle path shown on the picture as long as you don't unlock the gate at the top path as well. Please let me know if there is a stone key the guide has missed so I can update it.


The first two stone keys listed here area easily reachable from the save point near the entrance.





The next two listed here are in the right-most building. This building has many floors, each blocked by a brown door. You can enter any of these doors as long as you find the stone key at the end of the room. The only required floor for the next sun key is the bottom one, which has the eighteenth stone key.






The next sun key is guarded by the area's boss. You can access it by reaching a blue switch from one the right-most building's bottom entrances.


Note
The sceenshot shows an extra sun key before getting this one. I got Sun Key #10, then #9 but it is more convenient to get #9 first from the right-most building.



The next three keys are in the top left-area of the level.

There are two stone keys in the top-left structure with the gray gates. They are in the same section but blocked by different gray gates.

#19


#20



You will use two sun keys to unlock the entrance to the next level. When you enter the next level you should have four stone keys and four sun keys.

This level does not have many keys. You can find two stone keys and one sun key here. There is also a stone key you can get from the first level with one of this level's items.

First of all, use the light rod from the previous level to charge a large orb that will illuminate the entire level. The orb is located somewhere to the bottom-right of the entrance.


There are two stone keys you can get after you get the ice rod. This first key is in the bottom-right area.



The next stone key that you can find with the ice rod is back in the first level. You can find a shortcut to this level near where you got the ice rod. From there make your way to the passageway located in the left-side of the level.



The last two keys require the grappling hook. The first key listed is located near where you get the grappling hook.



The last key is in the bottom-left area, guarded by a boss. Use both of the level's items to reach it.



You will then use a sun key to unlock the path leading to the next level. Before entering the door, you should have seven stone keys and five sun keys.

You can find one stone key and three sun keys here. This level has many sun key illusions.


The first two sun keys are located near the entrance. One of them is in the area to the left while the other is in the area to the right.





Advance up to the next area and go defeat the Asura to the left of the next save point. You can reach the last two keys from the same area with the red, blue, and gray gates. You can actualy get both keys before even flipping any of the switches here.





At this point you should have all of the real sun keys in this level. Before advancing to the next level you should have seven stone keys and six sun keys.

In this last level you will find last stone key as well as the room with all the doors you'll need to unlock.

The first key here is located near the entrance.



You now have the neccessary keys for unlocking the doors in the last area of this level. Unlock a yellow door to reach the Arachniamachina boss. Make sure you have eight stone keys and five sun keys. Eventually you will enter an area with eight brown doors and six yellow doors.



Congratulations! You can now head on to find the secrets.