These are all the games in the franchise:
The original Exile trilogy
1995 Exile I: Escape from the Pit
1996 Exile II: Crystal Souls
1997 Exile III: Ruined World
I've played and beaten these. You can get them for free now. The character building and interacting with other characters, and a number of other aspects of the game, are more complex than the later games in ways that made them more appealing and immersive to me back in the day, but that I might not have the patience for now. There are also alot of game mechanics that are not bugs but that are exploitable in unintentional ways. On replay I was able to win the hardest fights in the original without getting hurt because I'd figured out cheap ways to do it.
I abo####ely loved these games to pieces at one time, but even though there are some things I think they did better than the later games, I'm not really interested in revisiting them, partially because of the broken game mechanics, and partially because stuff I used ot think made them more immersive would now just annoy me.
Blades of Exile - This game came with three shorter scenarios, and an editor that let you make your own and put them online for other players. I only ever played the first scenario, which was part of the free demo.
I will say that I personally prefer the old tiled graphics that the Exile games used to the look of any of the Avernum games.
The Original Avernum Games:
2000 Avernum 2
2002 Avernum 3
2004 Blades of Avernum
These are remakes of the original Exile trilogy. I have only played Blades of Avernum, and have only played part of the original scenario, which is a remake of the BoE scenario that I'd played on Exile. It does have one more manufacture made scenario.
Basesd on BoA, this era is, to me, clunkier to handle and and uglier looking than either Exile or later Avernum games. It retains some of the things that I miss in the later Avernum games, but also retains some things I'm glad that they dumped.
It sold poorly because the scenario editor was considered alot harder to use than the original BoE scenario editor, and creator Jeff Vogel said that it was the hardest of any Exile/Avernum game to make, so it's not getting a second remake.
The second Avernum Trilogy
2005 Avernum IV
2007 Avernum V
2009 Avernum VI
I've played all of these, after played the Exile
trilogy but before playing the latest versions of Avernum. I'll give some thoughts on them below. The graphics and gameplay become more polished from IV to VI. I remember some things about of IV being clunkier than the games that were made later, but it's better than BoA.
One thing that makes this different from any version of the original trilogy is that these don't have an overworld distinct from the towns/dungeons, which all the other games do.
The Avernum Remakes:
2011 Avernum: Escape from the Pit
2015 Avernum II: Crystal Souls
2018 Avernum III: Ruined World
note, fwiw, that the ": subltitle" are offitical parts of the game names here, like in the original Exile games, and that wasn't true of the original Avernum trilogy.
There are points where the streaminling and handholding go too far here, so these aren't perfect remakes of Exile, but overall I'd say that these games are certainly better than the original Exile games in everything, if you get over my preference for the original style of graphics. They're objectively better in that they don't have combat elements that can be unintentionally exploited.
One thing they tried to do with these games was to split up the main objectives so that players who didn't want to sink in the time to do everything would still get to feel like they finished something, and didn't just bail on the games. When I give my thoughts on the games, I'll address that.
They also all have a billion sidquests, many of which are optional, but that's not what I was talking about the previous paragraph.
Some brief thoughts on the most recent version of the first trilogy, and on the second trilogy:
2011 Avernum: Escape from the Pit - This is the least plot-heavy and most sandboxy of any of the games. If you like exploration and worldbuilding then there's alot to offer.
It's also the one that does the best job offering multiple objectives that feel like they let you choose how much you want to do. There are three main quests that can be done in any order. You can do all of them in one playthrough, or just one or two. There is not endgame.
Because it's the first story, one of the best, and the one that does the best job letting you play just one of the main quests if you feel like it, I recommend playing this one first.
But if you prefer a strong story and don't like super-open ended, sandbox gameplay, it might not be the best fit for you.
Just as a note, this is the only game where you can only play as humans. The other games have three races. In the other games, your parties can (and generally are) multi-racial, and the races you pick don't affect the story or objectives.
Some people do prefer the earlier vesions, so if you have both versions of the first Avernum, maybe dip you toes in both and see which one is for you.
2015 Avernum II: Crystal Souls - This is generally, and I think rightly, considered the best story in the series. It uses most of the overworld from the original game, but also opens up some new areas to explore. The first third or so of the game is more linear than the first game, but after that you have more freedom as to what order you want to do things in.
I think this is the game that does the worst job of just letting you play part of the objectives. Again there are three main objectives, but you have to do 2/3 of one of them to open up the other two, and because of the way the story works, it feels like you're bailing on the game if you don't do the entire thing. However, because it's the series best story and best game, I don't find this to be that much of an issue.
If you'd rather start with something that has a stronger story and doesn't start off open endedly, you can start here. If you only have the old vesion of this one, you can give it a whirl. Some people like the first Avernum trilogy better than the most recent version. And to be fair, I only played Blades.
2018 Avernum III: Ruined World
This is the biggest game, and it takes place entirely in a different location than the rest of the series. It's good, but I don't find it as fun to explore as the first two. This one has a defined passage of time. There is no point at which you lose if you take too long, but things in the game change. It's the only on where that happens.
There are five main "plagues" that you have to defeat. You can defeat all of them if you want, but you only need to do the first or second (objectively there's not a "first" or "second," but that's an easy way to describe them without getting into the story), third or forth, and then the fifth is mandatory, and then there's an endgame you need to do to finish the game.
Avernum IV - If you're playing the most recent versions of the first trilogy, then this is the oldest and clunkiest game. You're back in the area of the first two games.
There are a bunch of main quests, tbh I forget how many, and an endgame. You can do the endgame without comleting anything else, so this one is good for people who don't want to be obliged to anything. Which quests you've done affect the ending, but it's really just a bunch of text that pops up at the end telling you how things shook out.
Honestly, I didn't hate this or anything, but it's kind of a slog. The story really just lazily rehashes stuff from the earlier games. If you love any version of the first three, you'll probably want give it a try. If you care about the story of Avernum, I think it's the most skippable in that regard as well.
Avernum IV - This is the most linear of the six games, and instead of serveral main quests to chose from, there are a bunch of places where you can only take A or B quest. you can also side with the bad guys and get a different ending.
It's also one of the two games that take place mostly outside of the area where most of the games take place.
Most people agree that it has alot of gruelling, annoying "boss" type battles that are on the whole a downside.
So this one doesn't offere the choice of how much you want to play of the game. Instead it tries to give alternate options that might make it more replayable.
Avernum VI - This is a really perfect ending to the trilogy, which my pick for the second strongest story. It's also polished in wasy that give it an avantage over the games made before it. It's less linearl than V, but more than the first three. As I remember, the big choices come late in the game, when some main quests pop up and you need to do at least two of four to trigger the end game. But before that, I think you have to do some earlier main goals. I don't completely remember at this point.
Rankings from best to worst
Avernum II: Crystal Souls
Avernum: Escape from the Pit
Avernum III: Ruined World
Recommended for fans
Worth checking out if you're a die-hard fan