The game’s difficulty level mostly depends on how well you understand its combat and class mechanics, so if you’re unfamiliar with D&D rules and have never played a pen-and-paper RPG before (which was my case), your first playthrough may be a tad daunting. Still, it is possible to bungle through without completely mastering all the system’s intricacies, and the game lets you save anywhere, as long as you’re not in combat. Just be prepared for some challenging encounters. This includes the final boss battle, which actually pits you against several antagonists besides the big bad, Sarevok. He’s an interesting villain in several respects, and his story is built up some more in the sequel, thus adding quite a bit to his depth. To be more specific would be to foray into spoiler territory, but he’s definitely one of the more compelling villains produced by BioWare, as witnessed by the several mods dedicated to him in Baldur’s Gate II.
You should also be prepared to keep your party healthy, especially in the earlier stages of the game. Because not only is it Game Over if your protagonist dies, but your only recourse for reviving dead companions is trekking to the nearest temple, where you can buy a Raise Dead scroll. Either that, or stock up on them beforehand. Clerics eventually learn this spell, but only at level 9, which you might not reach in this game. Jaheira also learns Harper’s Call, but the same issue applies. And one more thing: it will only work if the victim’s corpse is in one piece. If they’ve exploded into meaty chunks from a critical hit, then they’re gone for good, and you better hope you have an earlier save. Also be careful if you encounter slimes and make sure to check the complexion of your team after the fight. If anybody’s turned green, just reload; otherwise, they will die in a few minutes, and you won’t be able to bring them back.
The game has a non-linear structure: there’s a guiding storyline, but you’re free to explore and take on sidequests at pretty much any point. In fact, depending on which companions you recruit, you may be required to complete their sidequests in order to secure them. About half of the cast has something they need help with when you recruit them, and if it’s not resolved in a timely fashion, they’ll leave. They do give you fair warning, though, so you have time to wrap things up. And if you forget which quests you’ve undertaken, there’s a “Journal” section in the menu that helpfully keeps track of them for you. The expansion, Tales of the Sword Coast, beefs up the sidequest department by adding a very large optional dungeon called Durlag’s Tower and several other sidequests. Although I wouldn’t advise tackling Durlag’s Tower until the later stretches of the game.
All travelling is done on foot, which can become tedious. The world map is subdivided into interlinked areas, which you uncover by exiting a connecting area via the correct side of the screen (east, north, west or south). You may also run into random encounters while travelling between areas. There’s a day-and-night cycle, which is indicated by a clock at the bottom left of the screen. It determines which enemies and NPCs appear in a given area and also comes into play in certain quests. As for the areas themselves, they are initially obscured with what is commonly referred to as the ‘fog of war’ (i.e. the screen is black, and the area gradually becomes visible as you explore). I’m not exactly sure what purpose this serves, as, even without the ‘fog of war’, NPCs and enemies that are beyond the party’s field of vision don’t appear onscreen. Each area is also very large, and distances between areas are measured in in-game hours. This means that, after a while, your characters will become tired. This is signalled by a red symbol on their portrait and a voiced complaint along the lines of “even the most prolific adventurer must take some time to rest” (Coran). Fatigue is cumulative and gradually lowers the characters’ Saving Throws, so resting promptly–via a menu option–is in your best interests. Resting also recovers health, reverses negative status effects and recharges spells. If you’re in town, it entails going inside a building or an inn first, as guards will prevent you from resting in the street. If you’re in the wilderness, there’s a chance that your rest will be interrupted by an enemy attack, which can be dangerous if your party is a bit banged up. Again: realistic, but hardly practical.
Quite a few items unfortunately require identification before you can figure out what they are. This is achieved via the Lore score, which is a Bard’s specialty. Mages and Thieves can also serve, although they’ll be less likely to succeed. Failing that, you can also bring the item in question to a store to have it identified for a fee. Or use an Identify scroll.
Other item-related woes are present. Say you find a Ring of Protection. Should you find another one, you won’t be able to equip both on the same character; this applies to any item which has ‘of Protection’ in its name. I have no idea why this rule exists except for arbitrary annoyance. Moreover, inventory space is limited. Each character has three quick item slots (i.e. items which can be used from the combat menu during a fight: this is where potions, wands, scrolls and enchanted items should go) and 16 inventory slots. It’s true that, when you’ve got a full party of six, this allows you to lug considerable amounts of swag, but that doesn’t make your pockets bottomless. In addition, each character has a weight limit, determined by their Strength. If you overshoot that weight allowance, they’ll be encumbered, and will either move slower or be unable to move at all. In short, hand your heavy stuff to your frontliners.
Other elements that make inventory management an issue are the fact that you need to replenish ammo and the fact that there’s an iron crisis in the region. This means that all iron is tainted, so any non-enchanted weapon (i.e. any generic weapon which doesn’t have a +1 or +2 in its name) has a chance of breaking during combat. If you don’t have a replacement handy on the spot, this can be handicapping, but you’ll need to find the right balance between lugging around a bundle of spare swords and having enough inventory space left over. Still, despite being distinctly annoying, this stops being a problem once you’ve outfitted all your characters with enchanted weapons.
That being said, to make your life easier, don’t pick up every single bit of loot that drops and sell off anything you won’t need for your characters or for a quest. Sell weapons and armour in bulk, if possible, otherwise you’ll gradually get less money if you keep selling the same item to one merchant. Also worth noting is the fact that most shopkeepers–with the exception of smugglers or thieves–won’t buy stolen items (which a character has pickpocketed from an NPC or stolen from another shop), so make sure you’re going to use an item or have someone to sell it back to before pilfering it.
There are two important elements of your party’s interaction with NPCs: Charisma and reputation. Charisma is basically the leadership attribute: it determines how well a character can hold a team together, and how favourably other people respond to them. This is why it’s important to place a character–not necessarily your protagonist–with high Charisma as party leader (in other words, in the first party slot). High Charisma lowers the likelihood of inter-companion conflicts and morale failure, grants you a discount in shops and sometimes even nets you better quest rewards. On the other hand, low Charisma may cause some quest givers and even some companions to refuse to have anything to do with your party.
Reputation has similar effects. It’s measured on a scale of 1 to 20, and can be gained by resolving conflicts in a helpful and chivalrous manner, or lost by getting caught stealing or murdering innocent people, for example. Alternatively, donating a certain amount of money to a temple can also grant a reputation bonus. Evil characters will leave the party if reputation rises above 18, and Good ones will bail if it falls below 2. If it falls as far as 1, Neutral characters will leave as well. However, reputation that low is inadvisable even for Evil parties, as, starting from a score of 5, there will be a likelihood of attack by a group of mercenaries every time the party enters a new area. Moreover, any reputation below 10 will cause a gradual price increase in shops, up to the point where merchants will simply refuse to sell their wares if it hits 1. Conversely, starting from a reputation of 15, shop prices will gradually go down, reaching a 35% discount at 20. In effect, this means that Good parties will have an easier time of things. Evil parties will have to maintain a precarious balance: a low enough reputation to keep companions happy, but high enough to avoid attack and not be too taxing on the wallet. Although I’m not sure I agree on that last restriction: surely an Evil character could simply bully a shopkeeper into giving them a discount?
A final remark: when exploring dungeons or areas where spiders are susceptible to be active, do keep a Thief on point with “Detect Traps” active. There’s quite a lot of them around, and some are particularly deadly. The same thing applies every time you find a chest or any other container with loot, especially if it’s locked. Better safe than dead, I always say.