You can unlock 12 achievements worth 170gs with the trial. There is no time limit so you can play as often as you'd like.
Story:
Collectables:
Rear-view mirror in car or Puddle outside car.
On the door to shack in front of the car. Next to the red wood/cross.
On the desk in the Secret Chamber. Behind the three gold pots.
Misc:
On casual it will force you to play this. On expert you have to choose. The name is a little misleading, you match things that go together a la a gun and bullets.
HoS scene guide:
http://abload.de/img/06-04-2018_15-10-35aai9qsl.png