20. Baldur's Gate II: Enhanced Edition (BioWare/Beamdog Software, 2013)
Probably the best-known and beloved of the Infinity Engine games, and it isn't hard to see why - the game has a ton to offer with its 60+ playable classes, a great storyline with some very memorable characters (all of whom have their own questlines) and just some downright frantic combat, putting the high challenge of D&D into a game with plenty of creative tactics. It can get frustrating at times with overpowered enemies that all but require using engine exploits to succeed (Beholders and Illithids in general) but as far as RPG experiences go, this is one of the best you're likely to find for D&D games. As well as BioWare's best game by far.
Quake is a game with a complex history, beginning its life as an action-RPG titled "the Fight for Justice", slowly changing over the years to incorporate a 3D engine and ultimately turning into a shooter with some fantasy and Lovecraftian elements. That ended up being no bad thing, though, as Quake was a great, fast-paced experience with a creepy atmosphere (in no small part due to featuring audio design by Trent Reznor) and some creative level design. It even brought us elements like "Rocket Jumping" which lent themselves to all sorts of crazy (and impressive) speedrunning stunts, as well as some killer mods that would become successful franchises in their own right like Team Fortress. Even with its chunky, blocky 3D models, grainy textures and choppy animation overall, Quake is another classic title from Id.
The followup to Blizzard's mega-hit Diablo, the second game in the franchise upped the ante in almost every way. Featuring faster gameplay, a choice of five new classes (seven in the expansion) each with their own variety of skill sets and equipment choices, and of course a plethora of new quests, items, bosses and challenges to undertake. It also featured multiplayer for up to eight simultaneous players, who could choose to tackle dungeons, gain levels or just duke it out in battles to the death. Other new features, like "Rune words" and the ability to combine items and reroll equipment properties would also become staples of other games in the genre. Once again, a major hit for Blizzard that continues to be fun even today. There are even a few killer fan mods available for those tired of the stock game.
15. Thief Gold (Looking Glass Studios, 1998)
Looking Glass returns to the list with the first entry in what is unquestionably my favorite stealth franchise of all time: Thief. Thief Gold is an update of Thief: The Dark Project, adding in three new levels as well as some minor tweaks to existing ones to make things more in line with the revised storyline. But what makes Thief so great? Well, the gameplay, for one, which requires the player to use shadows and diversions in order to draw enemies away so they can slip past unharmed. To that end, the player also has a wide variety of tools to utilize - flash bombs, gas arrows, mines, rope arrows and noisemakers to name a few. Also adding a nice twist to things was the fact that it was one of the first objective-based games out there - instead of just killing everything in your path, you now had specific goals to carry out in each stage, and the less attention you attracted along the way, the better off you were (not to mention that the higher difficulty levels forbid you from killing people anyway). Of course, beneath it all was also a menacing atmosphere and pretty solid storyline involving the resurrection of a dark god whose existence is a threat to the world itself, but that tends to take a backseat to the thrill of the heist the game so effectively pulls off.
13. Ultima IV: Quest of the Avatar (Origin Systems, 1985)
Ultima IV is very possibly the most unique CRPG ever made, and that is saying a lot. Rather than having you quest to defeat some big bad guy, this game instead proves to be a journey of self-improvement, having the player atone for some of their more... questionable actions in the previous Ultima titles by embodying the eight virtues, venturing into the stygian abyss and recovering the Codex of Ultimate Wisdom to push Britannia into a new age of prosperity and spiritual guidance. And yes, this does entail actually being a good person in the game - righting wrongs, resisting the temptation to steal and kill, and showing compassion, valor and humility whenever needed. Of course, there are still plenty of puzzles to solve along the way and quite a bit of combat to endure, but that takes a backseat to the overall theme of being a virtuous character. A great concept with a fantastic execution.
12. Undertale (Toby Fox, 2015)
Taking inspiration from the SNES classic Earthbound for its simple yet charming visual style, quirky sense of humor and sincere charm, Undertale also adds an element of player choice to the proceedings. The player is given full reign over their actions in this world - they can fight their way through everything, or resolve battles more diplomatically (which entails all sorts of silly dialog options), and each choice is perfectly valid and can lead to one of several endings. The game's combat system is also innovative in itself, being based on timed button presses to land attacks and a shoot-em-up styled bullet dodging experience to avoid enemy attacks (which you will have to get very good at in order to reach the Pacifist ending). The game is also overly short, but in an era of 50+ hour games that are that long just for the sake of being that long, I don't mind this fact one bit. Undertale is a stroke of genius and deserves all the acclaim it's gotten.
11. Fallout 2 (Black Isle Studios, 1998)
An excellent title from Black Isle, and one of my favorite games of all time to boot. The original Fallout definitely had charm to spare with its open-ended character development, multiple ways to complete objectives, heavy world lore and a wry sense of humor despite itself, but Fallout 2 took all of that and expanded upon it tenfold. Bigger guns, new monsters, a wide variety of recruitable characters, and tons of new locations to explore and characters to interact with - some lovable, some you just love to hate. There's also a reworked Perk system and a very handy new feature in the form of a drivable car, which makes transportation around the landscape more convenient and gives you plenty of extra carrying capacity to boot. A stellar RPG experience from beginning to end and, again, one of the finest games in the CRPG genre.