Island Demo question

Hi, I have just downloaded this demo but there are some errors after opening in Unity 3.5, does anyone know what should I change to make it work (I have just opened Unity for the first time so I have no experience with it whatsoever yet!)

Or maybe someone has some links to the very basic tutorial about making the FPS camera/player script for the game, I found the old one for Unity 1 but on the forum they say it will be a bit confusing as since then Unity has changed and some of the code is obsolete, so I am looking for just a basics in v3.5

What error?

On opening it shows this message:

Assets/Scripts/UnderwaterEffects.js(23,46): BCE0022: Cannot convert
‘UnityEngine.GameObject’ to ‘float’.

If I try to run it it adds also this:

All compiler errors have to be fixed before you can enter playmode!
UnityEditor.SceneView:ShowCompileErrorNotification()

Assert in file: C:/BuildAgent/work/b0bcff80449a48aa/Editor/Mono/SceneView/SceneView.cs at line: 1317

click on the errors in the console. When you do that it should highlight a file in the project view of what is causing that error. Delete the files.