Diablo II and its Lord of Destruction expansion set comprise one of the best-selling PC games of all time. Many players get into it by purchasing the Battle Chest, which includes the original Diablo, though many have probably never even tried the game.
In a fit of historical curiosity I recently installed Diablo to see the kind of changes Blizzard made when putting together the sequel. Some of Diablo's mechanics are the same (or very similar) as its successor, but overall I found it a confusing experience when things didn't work out as I had expected. Still, I persisted in playing Diablo, and now feel more qualified to write a guide for Diablo II players wishing to take a trip back in time to the original Diablo experience.
This is not an exhaustive change list, it is primarily geared towards getting players familiar with D2 up to speed in vanilla Diablo quickly, and as such it covers the topics new players are likely to misunderstand. Suggestions, questions, comments and additions are welcome: please send them to me using the contact info in the footer.
Single vs Multi-PlayerIt didn't originally start out this way, but Blizzard has made good strides in eliminating the differences between Single and Multi-Player play in Diablo II, to the point where the SP experience is very nearly equal to the BNet one (with the obvious exception of other players).
This is not the case in Diablo. The single-player game is somewhat persistent: when you save your character, the game is saved with it, and loading will pick up in the exact spot that you left off. When starting a new game, Diablo will randomly generate a set of quests that you may complete in addition to some pre-set ones, and these may come with quest-specific rewards (unique items, etc). You must also manage saving your game yourself - if you quit without saving, your progress is lost. When you die in single-player, your game ends, and your options are only to reload from your previous save or start a brand-new game while re-using the same character. And, finally, the single-player game allows you only Normal difficulty - there is no Nightmare or Hell mode.
Multi-player games do not create persistent games - only characters. There are NO random quests in multi-player, only four preset ones which never change. There are no quest items. When you die in Multiplayer, you are given the option to respawn in town, just like D2. (There are scrolls and spells that may allow you to revive fallen teammates, too, so don't be so quick to revive yourself back in Tristram). And, finally, multiplayer Diablo gives you the choice of difficulty levels: you must be level 20 to start a Nightmare game, and level 30 to start a Hell game. For this reason, many players choose to play solo multiplayer games instead of single-player, as the character offers further challenges after completing the game on Normal difficulty. (Single- and multi-player characters can't be converted from one to the other.)
Character ClassesDiablo has only three character classes, and the lines between them are much blurrier than in Diablo II.
There are no distinct skill trees in Diablo. All classes share the same "pool" of available spells, though each class comes equipped with a single unique (and generally useless) skill. When you level up, you gain only stat points - spells are instead learned by reading a "Book of [spellname]" when you have sufficient Magic stat points to comprehend it.
The primary difference between character classes is the class-specific maximum limit placed on each stat, along with a handful of class-specific items and some subtle differences in cast speed, block rate, swing speed, etc. For example, a Warrior is capped at 250 (base) Strength, while a Sorcerer can obtain only 45 points. This translates indirectly to a limit on spell levels learnable by a Warrior and equipment limits usable by the Sorcerer.
Finally, while character balance has been extensively tweaked, managed and adjusted for D2, character classes are fairly imbalanced in Diablo. Magic is far more powerful than the best weapons findable in-game, so by extension, a Sorcerer is the power-player's class of choice and Warriors fall closer towards the weak end of the spectrum.
Character NotesUnlike D2, your character's mana and HP does not regenerate. There is a Healer in town who will restore your HP for free, but there is nobody to offer the same service for mana. So, you will have to rely on potions to recover your mana (and to a lesser degree, your hp) for most of the game. Other ways of recovering life/mana: Wells found in the dungeon, healing scrolls and spells, learning a new spell from a book (recovers some mana), leveling up, mana/life leech items.
There is, obviously, less equipment available in Diablo: you don't get to wear boots, belts, or gloves. Your belt can hold up to eight items (potions and scrolls). Additionally, you must carry your gold in your inventory (up to 5000 Gold in one stack). When you die in a multiplayer game, you will drop the items currently equipped on your character, and they are free for others to pick up! You'll have to go recover them up before exiting or starting a new game, or they are lost forever. Your corpse does NOT come back to town. Therefore, be extremely careful not to die when surrounded by a horde of monsters - it will make body recovery much more difficult.
There are three types of resistances in Diablo: fire, lightning, and magic (all spells that do not fit the other two elements). Shield-equipped characters have a chance to block any spell which they have 0% resistance to, but once you have some resistance, you lose the ability to block those types of spell. This is both good and bad: at low levels, it may be better to block spells, but at high levels with certain enemies it is easy to get block-locked and become unable to act - so resistances are a must.
PacingThere is a common complaint among new Diablo players that the game is much slower paced than Diablo II. To some extent this is true - after all, D2 offers the "jog" feature to move much more quickly around the map. It is not possible to Jog in Diablo.
However, there are two things that change the situation somewhat. First, maps in Diablo are much smaller (more compact) than they are in Diablo II. Thus, jogging would be unneccesary for quick movement, as you can cover the map pretty easily anyway. Second, once your character learns Teleport, the game becomes much much quicker. Remember that all classes can learn spells, so even Warriors may use Teleport to get around more rapidly.
Dungeon ElementsThe world of Diablo is much smaller than D2. You will never travel outside of Tristram, and the only dungeon is beneath your feet. There are 16 levels, broken into groups of four, and as you progress downwards the difficulty of enemy monsters increases. There are four entry points into the Dungeons scattered about town, and gaining entry to each depends on whether you are playing Single or Multi-player. For single-player games, as you find the proper exits from the dungeon at levels 5, 9, and 13, the Crypt, Caves, and Hell open up for you. (The Cathedral is the entrance to level 1 and is always available). Multi-player characters simply find their entrance barred until they reach an appropriate character level to gain entry.
You will probably notice a rigid grid system imposed on everything in the dungeons - this will affect your play more significantly than you might realize. Everything must occupy a square (or be in motion between two squares). This gives you some advantages, such as being able to set up bottlenecks in doorways or limit the number of enemies that can surround you. Adjusting to the gridded system takes a little time.
Shrines in Diablo play a much more important role than they do in D2. Shrines may have positive or negative effects, and are often permanent! They are identified by a special prefix on the first few levels - ensure that you know what the outcome will be before clicking or you may lose spell levels, max. mana, equipment or stats. Later levels do not identify the shrines uniquely so seriously consider whether a click is worthwhile or not.
Lastly: there is a special monster which may appear in levels 3-5 called the Black Death. These bright yellow zombies permanently take away 1 max hp every time they successfully hit your character! You should consider using ranged attacks or spells to eliminate them before they get a chance to get close.
Friendly FireRogues and Sorcerers take special note: your arrows and spells can damage your teammates, though you are not hostile to one another! You will have to develop cooperative strategies that work around this issue.
ItemsItems underwent a serious overhaul in D2, but in Diablo, you will find only three types: normal (white), magic (blue), and Unique (gold). It is not necessary to identify an item before using it, and you may be able to use the abilities of the item without knowing what they are, but beware: there are negative magical affixes (reduced damage, lowered durability, etc.). These "cursed" items sell for virtually nothing with the shopkeepers.
Identifying items is not a free service. Deckard Cain charges 100 gold per item for identification. You may also purchase or find Identify scrolls to do the job yourself, but it is more expensive than having Cain do it.
There is no Stash in Diablo. Single-players may safely leave items on the ground in town and they will stay between save/load cycles, but when you start a new game, only the items carried on your character come with you. Also, multiplayer characters keep only their inventory between sessions - so pick everything up before you log off!
There is no way to highlight items on the ground. D2 players are used to hitting the SHIFT key every few seconds to scan for loot, but Diablo forces you to keep your eyes and ears open for things to pick up. Be especially mindful of checking around monster corpses, behind tombs, etc. when looking for dropped stuff.
When item durability reaches 0, the item is destroyed entirely. Everything is fine up until you lose that last durability point - then, the item simply disappears from your inventory. For armor, durability is lost by taking hits. Melee weapons lose durability through hitting enemies. Bows do not use arrows, but instead have a chance to lose durability whenever they are fired. The Blacksmith in town restores items to full durability with a Repair, but at a price (of course).
As mentioned above, two classes have unique abilities to work on items: the Warrior can repair items and the Sorcerer can put charges back into staves. These actions reduce the maximum durability or charges of the item (respectively) and should not be used except in extremely dire circumstances.
Some other items are now findable in Diablo, however. Scrolls come in all varieties of spells, and afford a one-time casting of the listed spell, with lower magic requirements than actually learning the listed spell. Spellbooks will teach you new spells if you can read them.
MultiplayerDiablo came in the days before modern ethernet networks were highly popular, and sadly it does not allow TCP/IP play over LAN. You may attempt to get one of the other methods working, but most players will hop on Battle.net instead. Here are some of the differences.
You may have only one Character per Battle.net account, and your Character Name determines the Account Name. So, if you wish to have the account "WazootyMan", you must name your character WazootyMan and then attempt to connect. Also, all Battle.net games are "open" games - that is, not hosted by Blizzard's servers. This has the unfortunate side effect that a vast majority of BNet games are filled with cheating players, hacked and duped items, and unscrupulous play.