There is an exploit you can use to get all the hard time attack items, without actually doing hard time attack.
If you do all normal time attack times, but don't pick up the items from the pool, you can choose to start NG+ on hard and all the items will still be in the pool, but will be the Hard Time Attack versions.
You pick these all up and you get all Hard Time Attack Items, then start NG+ on normal again and do the Normal Time Attack times again to spawn the normal items.
This allows you to get all items without having to do Hard Time Attack at all. Thank you to iahaleem for this tip.
It still worked on April 2019.
This trophy is awarded for getting all Time Attack Items together on a single save, which is possible because the game is set up slightly different than originally. Once you finish the game once you can select New Game+ from the main menu and do it on whichever save you want. So to get all items on the same save you choose New Game+ on one save on Normal or Hard and get all items, then once you’re done save and go back to the main menu and select New Game+ on the same save again on the opposite difficulty from before. You will still keep all the items you got from the prior difficulty, then can do the Time Attacks on the new difficulty and get all the remaining items.
Time attacks are started by pressing in front of the statues in the shrine. Items are awarded for every two colossi you defeat on each difficulty, and appear in the shallow pool in the back of the shrine. You need to go and pick up each one with to count as you having the item, and the trophy will be awarded once you have picked up all 16 items.
If you have done Time Attack on PS3 this trophy will give you no issues. Bluepoint fixed most of the problems present in the PS3 version, such as the endless shaking some Colossi do, so overall it is easier and basically all the Colossi can be done without any special tricks (such as Number 3). Times have also been altered in some, with some being reduced and some being increased, though the reductions were mostly on the longest ones before and the increases were on some of the harder ones (again, Number 3).
Time Attack Times:
First number is Normal difficulty, second number is Hard difficulty
1. Valus - 2:30/2:45
2. Quadratus - 3:30/4:30
3. Gaius - 6:00/6:30
4. Phaedra - 5:00/6:15
5. Avion - 5:00/4:15
6. Barba - 3:30/6:00
7. Hydrus - 9:00/7:30
8. Kuromori - 6:00/7:00
9. Basaran - 5:30/5:45
10. Dirge - 5:30/5:45
11. Celosia - 4:30/4:15
12. Pelagia - 8:30/9:30
13. Phalanx - 12:00/10:15
14. Cenobia - 9:00/8:15
15. Argus - 7:30/10:00
16. Malus - 9:45/10:45
Colossus #16 (hardest one) hint:
I had a problem on his right palm.
Once I hit Spot 1 on his left shoulder and jump on his right palm, colossus didn't move his hand to the shooting position to shoot the arrow to his Spot 2 on the left shoulder.
So I hit his right palm with sword and after that colossus move his hand so I can shoot that second spot on the left shoulder.
You will need around 2:15 minutes to commit all hits on his head and he will be dead.
Most of the times can be beaten just by playing each fight normally like you would do in a Normal/Hard playthrough, as most of the times are very reasonable (or way higher than necessary). The times that are higher on Hard are typically Colossi that have extra damage points, and the ones that are lower are ones that don’t have extra damage points.