Hang onto the hawk for more than 30 seconds
We found a location where one hawk flies particularly low to the ground at top left corner of B5 (see video), but hawks will also sometimes fly over your head as you ride Agro. If you can time it just right, you can leap from your horse’s back and grab the bird. Not counting any lizard tails you may have eaten, you need to defeat about half of the colossi to have enough stamina for this task.
Acquire all items available in hard time attack
You can fight any of the 16 colossi in hard time attack mode by praying (press O) at the foot of the statues inside the Shrine of Worship during a hard playthrough. For every two that you defeat, Dormin will drop an item into the small pool at the back of the shrine. Here is a list of the items and the order in which they unlock:
1. Harpoon of Thunder: Long range spear that damages colossi
2. Sword of the Sun: Can reflect sunlight in the dark
3. Fruit Tree Map: Shows all fruit on your map
4. Shaman’s Cloak: Increases your defense
5. Lizard Detection Stone: Shows only nearby lizards on your map
6. Shaman’s Mask: Increases your defense
7. Cloth of Desperation: Can be used as a parachute
8. Queen’s Sword: The sword from Ico, which kills a colossus in one hit
Max out stamina bar
There are two ways to increase your stamina: defeating colossi (not including time attack) and eating white lizard tails. However, lizard tails only slightly increase your stamina, so relying solely on tails can be very time consuming. It’s easier to simply beat the game repeatedly by defeating all 16 colossi, since you get a nice boost to your stamina and HP with every victory.
Endure being sucked into the light for over 1 minute in the ending
You should have enough stamina by the end of the game to accomplish this task even if you haven’t been hunting lizards. Simply hang onto the steps in front of the pool for as long as you can by holding the grip button.
Hang onto the fish for over 30 seconds
We found a small lake in the lower edge of C3 (see above). Simply swim near a fish and hold R1. Not counting any lizard tails you may have eaten, you need to defeat about half of the colossi to have enough stamina for this task.
Max out HP bar
There are two ways to increase your HP bar: defeating colossi (not including time attack) and eating fruit. Fruit helps quite a bit, and fortunately there is plenty of it around. Just check the branches of any tree you come across.
Save at all save points
There are a total of 25 save points in the game. See the map for the shrine locations. Note that one of the save points is at the foot of the Shrine of Worship, where you begin the game, and the final save point is just past the Broken Seal, which can be opened after defeating the 15th colossus.