There are a lot of ways to play a sorcerer. Not everyone will solve the same difficulty the same way, and thus, with the same spells. I've wrote a walkthrough where I was utterly crushing every opponent using spells that many people just don't think good enough, and not using spell some people tell "must have" in this very thread.
Honesty, for a solo sorcerer, there is very few "must have"
Level 1: Magic Missile There is simply some enemy at low level that will be a pain to kill without that one.
Level 2: Nothing... Seriously, there is no "must have" at this level, even soloing. The best you can take is Mirror Image or Melf's for trolls. But they are not "must have".
Level 3: Skull Trap Just because of low level golems are a pain in the ass to kill with just Magic Missile.
Level 4: Stoneskin Bread and butter physical defense, and the only one you will truly need if you play intelligently at low/mid level... and by the end, you will need none at all Arguably, Fire Shield can help against Greater Werewolves, but I prefer just to have a bit a higher level before dealing with them than relying on a spell that consist to be hit to do damage
Level 5: Lower Resistance and Spell Immunity Seriously... how to you expect to win against creature with almost 100% MR without Lower Resistance? It's the most powerful MR debuff, stackable, and you can put three of them into a sequencor And Spell Immunity. Just because... Maze or Imprisonement are immediate gameover without it
Level 6: True Sight You can't hit with Lower Resistance what you can't see. And some of the most powerful enemy spellcasters have both MR and invisibility spells of high level
Level 7: Mordenkanein's Sword and Project Image I get CRAZY each time I see people say to raise int on a solo sorcerer because of Mind Flayers. Guys, once for all: A single Mordenkanein's Sword utterly destroy ALL the Mind Flayers of the game. There is absolutly NOTHING Mind Flayer can do against it. Summon it, send it forward. You won. And this is not only the Mind Flayers.... MS is hand down the best meatshield a sorcerer can have. Even better than companions. Get it. Abuse it. And Project Image? That's just like multiplying your spellbook slots by 7.
Level 8: Horrid Wilting The BEST damage spell of the game. Magic damage that no one as 100% resistance again, no friendly fire, fast to cast with the Vecna Robe, can be put in a friggin contingency so opponents get 3 in there face as soon they enter your field of view... Spell Trigger is arguable. It's a good boost for Lower Resistance
Level 9: Time Stop That's not that you can't win without... that's just that, sorry, that spell is a game breaker. You can win 99% of the battle as soon your succeeded to cast it before your opponent.
Epic: Improved Alacrity The twin of Time Stop, use them together, add the Robe of Vecna. Gratz, you can now successfuly cast 50 spells before your opponent finishes its first round of action
I'm almost pretty sure you can do 100% of the game only with the spells listed above, and some random damage spells to fill the low level needs (one of them has to be acid or fire, because... trolls) EVERYTHING else is optional. Serious.
Comments
I've wrote a walkthrough where I was utterly crushing every opponent using spells that many people just don't think good enough, and not using spell some people tell "must have" in this very thread.
Honesty, for a solo sorcerer, there is very few "must have"
Level 1: Magic Missile
There is simply some enemy at low level that will be a pain to kill without that one.
Level 2: Nothing...
Seriously, there is no "must have" at this level, even soloing. The best you can take is Mirror Image or Melf's for trolls. But they are not "must have".
Level 3: Skull Trap
Just because of low level golems are a pain in the ass to kill with just Magic Missile.
Level 4: Stoneskin
Bread and butter physical defense, and the only one you will truly need if you play intelligently at low/mid level... and by the end, you will need none at all
Arguably, Fire Shield can help against Greater Werewolves, but I prefer just to have a bit a higher level before dealing with them than relying on a spell that consist to be hit to do damage
Level 5: Lower Resistance and Spell Immunity
Seriously... how to you expect to win against creature with almost 100% MR without Lower Resistance? It's the most powerful MR debuff, stackable, and you can put three of them into a sequencor
And Spell Immunity. Just because... Maze or Imprisonement are immediate gameover without it
Level 6: True Sight
You can't hit with Lower Resistance what you can't see. And some of the most powerful enemy spellcasters have both MR and invisibility spells of high level
Level 7: Mordenkanein's Sword and Project Image
I get CRAZY each time I see people say to raise int on a solo sorcerer because of Mind Flayers.
Guys, once for all: A single Mordenkanein's Sword utterly destroy ALL the Mind Flayers of the game. There is absolutly NOTHING Mind Flayer can do against it. Summon it, send it forward. You won.
And this is not only the Mind Flayers.... MS is hand down the best meatshield a sorcerer can have. Even better than companions. Get it. Abuse it.
And Project Image? That's just like multiplying your spellbook slots by 7.
Level 8: Horrid Wilting
The BEST damage spell of the game. Magic damage that no one as 100% resistance again, no friendly fire, fast to cast with the Vecna Robe, can be put in a friggin contingency so opponents get 3 in there face as soon they enter your field of view...
Spell Trigger is arguable. It's a good boost for Lower Resistance
Level 9: Time Stop
That's not that you can't win without... that's just that, sorry, that spell is a game breaker. You can win 99% of the battle as soon your succeeded to cast it before your opponent.
Epic: Improved Alacrity
The twin of Time Stop, use them together, add the Robe of Vecna. Gratz, you can now successfuly cast 50 spells before your opponent finishes its first round of action
I'm almost pretty sure you can do 100% of the game only with the spells listed above, and some random damage spells to fill the low level needs (one of them has to be acid or fire, because... trolls)
EVERYTHING else is optional. Serious.