The Swedish game Drakar och Demoner went through a number of more-or-less controversial editions.
The original version was pretty much a straight translation of Basic Roleplaying + Magic World from Worlds of Wonder. Soon after that, what most old-school DoD players would call the "classic" version was published, rewritten to be a bit more cohesive but more or less the same. After that, the publisher created the Expert rules, which moved to a d20 system instead of d100 (but still roll-under), added a bunch of detail (particularly in combat, with the addition of hit locations), and vastly expanded the skill and magic systems. So far so good. There was also a new version of the basic rules there somewhere, but that was mostly fancying up the layout, no real rule changes.
The first major change to the rules was the version most people call Drakar och Demoner 91, or the 4th edition. This incorporated the detail level from the expert rules into the core rules, and moved to a character creation system that was a hybrid between the old random system and a point-based system (race and stats were fully point-based, but things like social class and starting money used a combination where you rolled dice and added points spent and checked the results on a table). This was fairly well received at the time, but in retrospect heralded a new direction. The game became a touch more class-based – in the old Expert rules, skills had a cost determined by some level of difficulty, whereas 4th ed split skills into Primary (things everyone knows a little about), Secondary (other), and Professional (a subset of normally secondary skills you get from your profession/class), with each category having a different cost. In addition, each profession had a special ability, which in previous editions was Not A Thing – in the old days, professions only determined what skills you could start out with.
The 4th edition rules also had a bunch of... shoddy things in it. The GMing chapter had been lifted wholesale from another game from the same publisher, to the point where examples still talked about Metropolice instead of city guards. The amount of money in the game had also been seriously inflated, which caused issues with compatibility with older material. There was also a chapter about poisons and drugs that had been lifted from a previous "sidegrade" set in Fantasy Japan, and the prices in that chapter had not been "adjusted for inflation". As if that was not enough, the publisher started releasing a rather large quantity of splatbooks with dubious balance, as was custom in the early 90s.
But that was nothing compared to the 5th edition in 1994, or as it was commonly known: Chronopia. Instead of the core rules being mostly setting-independent but assuming a sort of vanilla fantasy, the game was focused on a Huge Corrupt City, which was also customary in the early 90s. The game assumed you'd be playing inside this city, and the world outside only got the briefest of overviews. It was clear that the publisher was taking lots and lots of inspiration from Games Workshop and their general grimdarkness. Systemwise the changes weren't all that big compared to 1991, except some limits on power level were loosened (e.g. in the Expert and 1991 rule sets, skill costs increased at higher levels, whereas Chronopia made them linear). This edition was quite controversial but fairly short-lived, as the publisher went bankrupt a years or two later after the collapse of the domestic RPG market.
But the story does not stop there. In 2000 (IIRC), a new company appears: Riotminds. They get a license from the IP holders, and make a new edition. This is of course also controversial, as they create a wholly new system, with fairly strong class elements whereas classic Drakar och Demoner had always been strongly skill-focused. They even added levels. They eventually released a new half-version that was more skill-based, but by that time my interest had checked out. On the plus side, they have gotten plenty of accolades for the setting they made for the game, Trudvang.