Go to the secret island, find out what's going on there, and fight the Siren Head and other scary creatures.
The controls are easy to use. Right-clicking with the mouse lets you look at things, and Shift lets you run.
The Siren Head game has more than one ending, and all of them can be reached in less than 20 minutes. Here is a quick look at each one.
Ending 1: Escape
This is how most stories end. You have to keep going until you reach a dead end, where there will be a torn-up body. You need to look at the main pile of meat until your character says "I need to return to the truck. NOW."
There will be a Siren Head right in front of you, and you'll have to run as fast as you can back to the truck to avoid him. Note that he won't kill you until he starts moving. This is probably a bug.
Part 2: Death
If Siren Head catches you at any time, he will pick you up and tear you apart. This is what the game's "bad ending" is called.
Ending 3: Death in Secret
If you get back to your truck but Siren Head is nearby, he will kill you as you drive away.
Have fun and good luck!