Simple script that plays Kill the King automagically. https://codepen.io/jcoulterdesign/full/MWeZWxQ

Kill-The-King-Beat-Script.js

document.querySelector('div.game_intro__inner.start > p').click();
setTimeout(() => {
    document.querySelector('div.game_intro__inner.end > div > p.continue').click();
    var lastXp = 0;

    function loop() {
        var stage = parseInt(document.querySelector('div.ui > div > div.ui_progress__stage').innerText.slice(6));

        try {
            var xp = parseInt(document.querySelector('div.game_inner__footer > div.resources > div').innerText.replace('xp', ''));

            for (var idx = 1; idx <= 3; idx++) document.querySelector(`div.upgrades > div:nth-child(${idx}) > div`).click();

            if (lastXp <= 0) document.querySelector('div.nextPhase').click();

            lastXp = xp;
        } catch {
            document.body.onkeyup({ keyCode: 32 });
        }

        setTimeout(loop, stage === 9 ? 350 : 1);
    }

    loop();
}, 5000);

Kill the King Beat Script

🤖👾👑

Simple script that plays Kill the King automagically.

Instructions

1. Just go to the full game view https://codepen.io/jcoulterdesign/full/MWeZWxQ
2. Open your browser console (Option + ⌘ + J or Shift + CTRL + J)
3. Select the context script like as showed bellow
   
4. Paste the script on the console
5. Press Enter and just watch

Extras

Some extra scripts

Autoclick only

setInterval(()=>document.body.onkeyup({keyCode: 32}), 300);

Infinite battle (bug)

document.querySelector('div.game_intro__inner.start > p').click();
setTimeout(() => {
    document.querySelector('div.game_intro__inner.end > div > p.continue').click();
    var lastXp = 0;
    setInterval(() => {
        try {
            var xp = parseInt(
                document.querySelector('#app > div > div.game_inner > div.game_inner__footer > div.resources > div').innerText.replace('xp', '')
            );

            for (var idx = 1; idx <= 3; idx++) document.querySelector(`div.upgrades > div:nth-child(${idx}) > div`).click();

            if (lastXp <= 0) document.querySelector('div.nextPhase').click();

            lastXp = xp;
        } catch {
            document.body.onkeyup({ keyCode: 32 });
        }
    }, 1);
}, 5000);

easy peasy lemon squeezy