I feel like this game is actually two unrelated games bundled together: there's the combat system (the system you get a tutorial on when you start the game) and the Tropico-style resource management game. The combat is fun, but the story quickly falls to the wayside and you're dropped into a world map where you're told to invest in mines and visit general stores, which is entirely driven by dialogue-boxes. Sometimes, I guess, you end up in combat because you visited a dangerous location, but there's no real connection between the two systems. This might be exactly the game some people are looking for, but it's not for me. If you've seen videos of the combat system, don't be fooled: most of the game doesn't take place in that mode, and the story that the game claims to tell isn't really the story you get.
This is a fantastic RPG. It's based on official D&D rules, so if you have any RPG experience this feels very familiar right from the start. It's as solid a game as, say, Dragons Age: Origins. It doesn't leave much to be desired. It's a great game. To my "modern" eyes, I think it's better than, say, Baldur's Gate, because it feels a little more familiar to current RPG games in terms of how you play it, but it benefits from a great story, lots of lore, and a great world. It also works flawlessly in WINE on Linux, so go for it!
I never played Witcher and only bought Witcher 2 because it was one of the early games to be released on Steam for Linux. I bought it again, later, on GOG because it's well worth having. It's a keeper. It's a fun game set in a fascinating world that you want to delve into and learn more about. I don't know that I'd call it an RPG. Allowing for the fact that few RPG's on a computer can truly be a role playing game, Witcher *still* doesn't really qualify. You play as exactly one pre-defined character, and I rarely get the sense that player choices really matter that much. There are several major plot points that are predestined; you can't really change alignment or turn the tides of even subtle story arcs. That said, it's a really fun game. It's sort of a medieval third-person shooter, I guess, with heaps of controls and intricate combat. You might be playing a preset character in a mostly scripted story arc, but you definitely have plenty of options in how you play it. You can be a tank, a sort-of rogue, a mage; it's really up to you. There's plenty to choose from, and the world is nuanced and full of history and lore. It's a fun game, and it's on Linux. Buy it twice.
This game has a fascinating concept; you can switch between playable characters whenever you want, there are lots of neat ideas for puzzle gameplay, and there's combat, and a freakin' grappling hook. What more could you want? In practice, however, this game is clunky and difficult to play due to poor controls, bad depth-of-field, and an atrociously bad co-op mode. I've played through most of the game multiple times on multiple platforms in hopes that I was just missing..something, but the truth is that controlling your character is, while obviously possible, is awkward and inefficient. It's nearly impossible to stop on a dime, the gravity feels unnatural for no given reason, sometimes the controller is just mapped wrong (and modding controller scheme is only partially supported, and then not well). While you're struggling to get comfortable with your character(s), you also have the unfortunate problem that the gameworld is cluttered. It's beautiful to look at, but playing in it is a mess. You can't tell whether a fallen tree is just there for parallax decoration, or whether it's blocking your path; there's no depth perception at all. Sometimes there will be ditches or pits that you fall into because you couldn't see the pit in the first place. Fair enough, I guess, but then you spend 10 minutes trying to get out of the pit, but you can't figure out what object around you is "in front" of your character, "behind", or on the same plane. It's all trial-and-error, like a bad point-and-click adventure game, except instead of constant clicking for clues, you're clicking around just to figure out which way you can move. I've tried Trine 2 and found it just as useless. I stopped trying by the time Trine 3 came out.
I tried to like Trine, but in the end it's an average game with clunky controls, a very problematic depth of field, and poor co-op implementation. Even the idea of swapping out characters to inherit a different set of skills ends up being pointless in the end. The controls are horrible. You can re-map and try to work around them, but in the end you really have to be playing on keyboard and mouse - difficult if you're playing local co-op. Even if you do use a keyboard, the response time feels lazy. Characters stop running a few hundred milliseconds after you stop, or jump just after you press JUMP. Maybe it's not a literal delay, but there's just something "off" about the physics. Combine bad physics with "3d" 2d platforming, and it's maddening. You can never tell where on the plane you are. Are you behind that fallen log or about to trip over it? You'll never know until you try it. Mix in some combat and you have a pretty miserable experience; the combat is no longer fun because you keep falling into a hole that you can't see, and then you die. For added frustration, try any of this with local co-op. The screen can't contain both characters, so you both end up crippled because one of you can't get over a rock and the other is trying to run ahead. It's so frustrating, especially since far lesser games implement a simple zoom-out camera function to deal with the same problem. And finally there's the one hook that Trine had going for it: the ability to quick-change your character in order to play a different set of skills. I still like this idea and I hope some other game tries some variation of it, but in practice it's a gimmick. Why bother switching characters? why not just let me earn the skill? It's not like I ever have to do a fast-change of character in mid-air or anything exciting like that. It's a mystery that there have been THREE of these games, but I do not recommend Trine or Trine 2 (haven't tried 3).