These can be bought in the Secret Menu

Unlockable	How to unlock
Audio Commentary	5 Precursor Orbs after buying scene players 1-3.
Bad Weather	5 Precursor Orbs After Act 1-1.
Big Head Mode	3 Precursor Orbs After Act 1-1.
Blaster Damage Upgrade	6 Precursor Orbs After Act 1-9.
Dark Jak Invisibility	25 Precursor Orbs After Act 3-11.
Fast Movies	5 Precursor Orbs After Act 1-1.
Hero Mode	5 precursor orbs, after finishing the game.
Increased Blaster Gun Ammo Capacity	4 Precursor Orbs After Act 1-17.
Increased Peace Maker Ammo Capacity	4 Precursor Orbs After Act 2-19.
Increased Scatter Gun Ammo Capacity	4 Precursor Orbs After Act 1-17.
Increased Vulcan Fury Ammo Capacity	4 Precursor Orbs After Act 1-24.
Invulnerability	100 Precursor Orbs After Act 3-11.
Jak 3 Model Viewer	2 Precursor Orbs After Act 3-11.
Jak And Daxter Model Viewer	2 Precursor Orbs After Act 1-24.
Jak II Model Viewer	2 Precursor Orbs After Act 2-25.
Level Select: ACT 1	5 Precursor Orbs, buy it after Act 1.
Level Select: ACT 2	5 Precursor Orbs, buy it after Act 2.
Level Select: ACT 3	5 Precursor Orbs, buy it after Act 3.
Mega Scrap Book	2 Precursor Orbs After Act 3-11.
Mirror World	5 Precursor Orbs After Act 1-1.
Peace Maker Increased Radius	6 Precursor Orbs After Act 2-19.
Rachet And Clank Gun Courses	6 Precursor Orbs After Act 2-12.
Scatter Gun Rate-Of-Fire Upgrade	6 Precursor Orbs After Act 1-9.
Scene Player Act 1	2 Precursor Orbs After Act 1.
Scene Player Act 2	2 Precursor Orbs After Act 2.
Scene Player Act 3	2 Precursor Orbs After Act 3.
Scrap Book	2 Precursor Orbs After Act 1-24.
Slow Movies	5 Precursor Orbs After Act 1-1.
Small Head Mode	3 Precursor Orbs After Act 1-1.
Toggle Jak's Goatee	2 Precursor Orbs After Act 1-1.
Unlimited Ammo	50 Precursor Orbs After Act 3-11.
Unlimited Dark Jak	50 Precursor Orbs After Act 3-11.
Unlimited Light Jak	50 Precursor Orbs After Act 3-11.
Unlimited Vechicle Turbos	30 Precursor Orbs After Act 2-25.
Upgrade Vechicle Toughness	15 Precursor Orbs After Act 2-14.
Vulcan Fury Damage Upgrade	6 Precursor Orbs After Act 1-17.