collision-gate.js

"plr-gate":{
    conds: [{ // array of condition objects
        'if': { // all properties here are conditions to be evaluated
            "hasflag": "haskey" // tests for global flag of the given name
        },
        then: { // effects to take place if all conditions were true
            on: true, // collision takes place on the square
            stop: "b", // stops the marble motion, with animation "b" (bounce)
            setwalltype: "none" // makes the gate disappear
        },
        'else': { // if any condition in if-object was false, execute this
            stop:"b" // stop marble motion (on a neighbouring square, since object doesn't have prop on=true
        }
    }]
}, // ...

collision-key.js

// part of propertylist of collision definition object
"plr-key":{
    setwalltype: "none", // makes the key disappear
    setflag: "haskey", // sets a global flag with the given name
    on: true // collision happens when marble is on the square, as opposed to next to it
},
// ...more definitions...