hn.js

// ==UserScript==
// @name         Hacker News - Score like reddit
// @namespace    http://avalanchy.tk/
// @version      0.1
// @description  Swap score with the position
// @author       avalanchy
// @match        https://news.ycombinator.com/*
// @grant        none
// ==/UserScript==


var ranks = document.getElementsByClassName('rank');
var scores = document.getElementsByClassName('score');
var subtexts = document.getElementsByClassName('subtext');

var max_score = 0;
for (var i=0; i<ranks.length; i++) {
    var rank = ranks[i];
    var score = scores[i];
    var subtext = subtexts[i];
    var score_text = '0 points';
    var rank_td = rank.parentElement;
    var under_rank_td = subtext.previousSibling;
    rank_td.rowSpan = 2;
    rank_td.align = 'center';
    under_rank_td.colSpan = 1;
    if (!!score) {
        var score_text = score.innerHTML;
        score.innerHTML = i + '.';
    }
    rank.innerHTML = score_text.replace(/ points?/, '');
    var int_score = parseInt(rank.innerText);
    if (int_score > max_score) {
        max_score = int_score;
    }
}

for (var i=0; i<ranks.length; i++) {
    var rank = ranks[i];
    var int_score = parseInt(rank.innerText);
    rank.style.opacity = (0.5*max_score+int_score)/max_score;
}

score.css

// best looks with "Hacker News - Light Theme" https://userstyles.org/styles/89773/hacker-news-light-theme
span.rank {
  padding: 4px;
  background-color: #f60;
  color: #fff;
  display: list-item;
  margin-top: 4px;
}