1001 Spikes

					
Unlock Alternate Ending:

When you have the Key of Serpentis play level 10-7, ‘Jokulkyrkja’, in Antarctica. If you jump on the platform that has the strange serpent symbol it will lower you down into a Boss fight. You must now defeat the Boss by throwing knives at the crystals on the ceiling so that each section of the dragon platform you are riding on breaks. After the Boss has been defeated you will unlock Antarctica for ALL characters, Jim Hawkins, and the alternate ending.
Easy ‘Serpentine’ Trophy:

The Key of Serpentis can be found near the exit door in level 2-1. You will only be able to access it after unlocking Antartica and when using Aban Hawkins.
Easy ‘Stone Cold’ Trophy:

To earn this trophy you must complete Antarctica. The way to do this is to get the Key of Serpentis so you can unlock the final stage and Boss and then kill that Boss.
Key of Serpentis:

If you play level 2-1, ‘Rush into the Ruin’ at the Ukampa Temple you will notice to the right side of the exit is a unique block with a key symbol. If you remove this block with the symbol you will be able to enter a new area to the right of the exit where you will find the Key of Serpentis. Note: Removing the block with the symbol may require ALL Golden Skulls. 
Unlock Characters:

Complete the following tasks to unlock the corresponding ending.
Commander Video:

Collect 8 Golden Skulls.
Curly Brace:

Collect 30 Golden Skulls.
El Testigo:

Collect 26 Golden Skulls.
Jim Hawkins:

View the True ending.
Juni:

Collect 18 Golden Skulls.
President Thompson:

Collect 20 Golden Skulls.
Sugimoto:

Collect 16 Golden Skulls.
Tina Hawkins:

Complete Ukampa Ruins.
Zombie:

Collect 23 Golden Skulls.
Unlock Counseil’s Duty Free Shop:

When you have collected 12 Golden Skulls this feature will become unlocked. 
Unlock Lost Levels Mode:

Collect 10 Golden Skulls to play this mini-campaign that has new levels.
Unlock Antarctica Temple:

When you complete ALL the Akumpa Ruins levels you will unlock Antarctica Temple for ALL the characters and be able to view the True ending.
Unlock Tower of Nanar Cooperative Mode:

This feature becomes unlocked when you have collected 6 Golden Skulls.
Change Character’s Colour:

To be able to change a character’s colour you must collect four Golden Skulls.
Easy ‘Stone Cold’ Trophy:

You can get this Trophy easily by obtaining the key of Serpentis to unlock the final stage and Boss and then Killing that Boss.