It’s a simple truism that CRPGs were influenced by D&D. You might as well point out the influence of Space Invaders on shooters, or of Sherlock Holmes on detective fiction. But the interesting thing about Pool of Radiance is the way it exposes the things that other CRPGs typically don’t imitate about D&D (as it existed at the time). I’ve already pointed out a few — gaining experience points for discovering treasure, for example. Or the memorizing of spells: nothing that isn’t strictly D&D-based bothers with that. Mana systems are the norm, and even venerable Wizardry provided something more like what would become the mechanics of the Sorcerer class in third edition D&D.
There’s all the little details of the mechanics of resting: taking different amounts of time to memorize different spell levels, or the way you can rest for days to restore hit points very slowly. The amount of time you spend resting is significant, because random encounters are based on strict timekeeping by the DM — something that most actual D&D groups probably didn’t bother managing, but which a computer can do easily. Nonetheless, most other CRPGs simplify things by assuming that a rest is simply a rest. Likewise, PoR faithfully implements the D&D encumbrance rules.
A lot of D&D-influenced games have limits on what races can be what classes, but this is the only one I can think of that imposes maximum experience levels for specific race/class combinations, leaving only humans able to advance arbitrarily. This is another idea imported directly from AD&D, and it’s weird enough that I have to wonder what effect Gygax was trying for. Perhaps it’s more natural coming from a miniatures wargaming perspective; perhaps level caps are part of the basic mechanics of the other games he was playing, and allowing higher caps for specific combinations was a way to say that dwarves are better fighters than halflings and so forth. In which case unlimited advancement for humans was seen as a special treat for them, rather than (as it is from the player’s perspective) punishment for everyone else. Anyway, this isn’t something I expect to come afoul of in the course of PoR, but it’ll certainly affect which characters I choose to import into the sequel.
One of the really striking things is just how slow combat is. CRPGs typically get individual encounters over with quickly, so that a typical session involves many encounters, but it’s not unusual for a large encounter to take the entirety of a D&D session. To a large extent, this difference is because D&D involves humans rolling dice and talking to each other, things that a computer can do much more quickly. But even so, the less-risky encounters in PoR frequently come down to putting all your characters on autopilot and then making yourself a sandwich or something while you wait for the computer to finish up. Partly this is because it has to go and animate the movement of every individual creature in the encounter, partly it’s because most encounters end with chasing down the last few monsters who tried to flee the area but got stuck on a wall somewhere. But partly it’s because, in the original D&D rules, attempts at hitting opponents simply miss most of the time. (This is why Magic Missile is such an important spell: it never misses.) In other CRPGs (particularly JRPGs), it’s more common for most blows to connect, but do proportionately little damage.
Generally speaking, the history of RPGs has been one of simplification, of eliminating elements that don’t justify themselves in fun (and introducing new elements that do). And CRPGs have evolved in this way faster than pencil-and-paper ones, by virtue of their faster revision cycle. People have complained that fourth edition D&D imitated the mechanics of World of Warcraft, but if you ask me, learning the design lessons that computer games have to offer is a smart thing to do. Even at this early stage in the history of the medium, CRPGs had to pick and choose what aspects of the D&D experience they felt were valuable — Wizardry simply couldn’t implement the entire ruleset and still run on the Commodore 64. For keeping the details that other games left out, PoR probably seemed more sophisticated than its competition at the time, but it really represented something of a step backwards.
It’s worth noting some of the features of D&D that aren’t imported into PoR. There’s no food here. There’s no mention of material components for spells. Light sources aren’t needed; your entire party can see as well underground as in town, eliminating the need for torches or any kind of light spell. These are all things that I consider pretty important to the texture of old-school D&D — what, I can’t buy iron rations? — but they were considered to be too much trouble to include, even by the people who implemented the encumbrance rules. It’s especially notable that these are all things that were present in various episodes in the Ultima series — I think U7 had them all.