Okay making this a separate post because my thoughts got too long, but basically beginner STS1 advice for @possessionisamyth
As a note, I do not like building infinities or playing a perfect game every time, so expect that sometimes you will lose! Particularly at higher ascensions!!
My qualifications are over 1k of hours in the game + A20 on every character both on the computer and on mobile.
Think really really really hard about taking a curse in an event where it's optional. There are times when it's okay, but those times are very rare. If you have an option to give up max HP instead, that's usually the best option. Max HP is usually your best sacrifice in most events, unless you are ironclad and have enough healing going that just taking damage isn't a big deal.
You want card removes. You want them all the time. It should be your first priority at most shops you hit up. Usually you want to card remove strikes before defends, but keep it fairly even. There's exceptions, but that's a higher level of play.
Think about what deck you have and what deck you want to build. Take time to go look in the compendium and see what other cards are accessible to your character that could interact with your current cards. The compendium can be accessed at any time on the pause menu and it is your best friend!! Go check it often!! You often want to look for keywords that play well together or compounding effects.
Think carefully before just taking random cards. Try to ask yourself what you want the card to do for you before taking it.
Roles to fill: Card Draw, Energy, Block, Damage. Keep all of these needs in mind as you're picking your cards.
Now!! Specific characters:
Ironclad will be your first STS1 character. This is for a reason. His healing mechanism enables him to really teach you an important lesson in slay the spire: HP is a resource that you get to spend. Just like gold or energy, HP should be managed alongside these other options with the knowledge of where your heals are going to be. I have three ish primary synergies that I do with him.
Status-Exhaust. Ironclad in STS1 has status cards he can generate, and these pair very nicely with his exhaust engine. You generate status cards and then exhaust them out to fuel other effects. Feel no Pain is a really good card for this, alongside Dark Embrace, and Power Through for some nice safe wounds. Evolve is huge for solving your card draw, and Second Wind can take out a whole hand of statuses for a ton of block. Fire Breathing + Evolve + Some Statuses is an evil combo that you can and should go for. This folds into the next Synergy.
Block!! Barricade and Body Slam are fundamental for Ironclad block builds, though you can skate by without Barricade for awhile if you have solid card draw and can build the block fast enough to kill. Block builds and Body Slam in particular can help solve damage problems on Status-Exhaust builds.
Hp = Strength. Ironclad has cards that let him sacrifice HP, if you pair these with Rupture, you can start stacking strength quickly. There's a couple other strength sources, but I've found rupture to be the most reliable outside of inflame. You also really want to hunt down Limit Break and upgrade it to start doubling your strength. Relic sources of strength are also great and should be prioritizes.
Silent is my favorite character, and she can be spooky to play but the long and the short of it is she draws every card, she has so many knives, and she's poisoning everything. I love her so much. She can get away with taking more bad card rewards than other characters, since she has good card draw and discard options to cycle her deck quickly. There's 2 major options for her deck builds in STS1, and then she also has her draw/discard cards that factor into the other two. Adrenaline is one of the best cards in the game you can grab and it's hers. Footwork, Afterimage, and Backflip are also amazing cards that will help you survive to setup other stuff. Escape Plan is also generally good. Prepared is also amazing and should be a high priority upgrade. Tools of the trade is also basically always good. Piercing Wail is also your best friend, take it.
Your first major deck archetype is shivs. These are my favorite. Blade Dance is a pretty important fundamental, or Cloak and Dagger if it's all you can get. Strength gain is super useful with Shivs, as is Accuracy. Nightmare can be a huge bonus if you can get the energy to use it, because you can use it to copy Accuracy and now have a single Shiv doing like 20 damage on Turn 2. Finisher is also really helpful if you can get some Strength, and really helps take out mid-game stuff. Afterimage plays really well with shiv decks, and Shiv decks hate Timeeater.
Poison is her second major archetype, and for STS1 it is probably the stronger one. Noxious Fumes is a pretty good poison AOE/maintainer, bouncing flask is really good, Crippling cloud really helps get poison going, but her true power lies in Catalyst. Catalyst is the poison scaler. Catalyst is how you end up with an integer overflow amount of poison and break the game. Catalyst is your friend. It's my friend. It will kill all of us. Catalyst was not permitted in STS2 and probably for good reason.
The Defect may seem scary, but do not be afraid. The Defect is a friend :). I think people get spooked by the orbs, but honestly they are not that complicated. You have 3 orbs, Lightning (does damage), Frost (does block), and Plasma (gives energy). Dark orbs aren't real and should be ignored in STS1. You've got power and energy, but for Defect I actually won't give you archetype breakdowns since I think they might spook you off. Instead, I will offer you the following advice:
Frost orbs and Lightning are basically attacks/defends that cannot be debuffed by frail or weak. Your focus will never be altered by an enemy. So stack up that focus and Frost Orbs and you will live forever. You want all the frost orbs forever. Nobody can hurt you when you have frost orbs.
Defect THRIVES off of being able to clear or prevent self-debuffs, mostly around hyperbeam / Biased Cognition. Hunt down Core Surge or get Orange Pills (relic). This will help you.
"Rainbow" is a trick card that you look at it and you think "well it's a rare so it must be good" this is a lie. it is a terrible card. ignore it forever.
Electrodynamics is INCREDIBLY good for improving damage output and handling AOE. Unless you're doing a 0 cost deck, you absolutely want it.
Okay, I am being mean since the Watcher is my least favorite character and in my opinion her deck is poorly balanced. She actually isn't that hard of a character to play, despite what some people will say. Actually the reason I dislike her is I find her too easy overall.
The big thing with Watcher is to just pay attention to how you're giving yourself "routes" into and out of stances. At the start, if you want to play Eruption, you either have to be ready to block double damage, play Vigilance to get into calm, or kill. Without an upgrade on Eruption, that's 4 energy you need to be able to spend without being able to play anything else. So, a high priority for early watcher is picking up cheaper ways out of your stances, (empty body, empty fist or calm options) so you can safely enter rage mode. You can do Mantra builds, you can also just play calm/angry. Halt is really good and so is Follow up and Furry of Blows. Rushdown is great for solving card draw problems. Talk to the hand + Tantrum pairs quite nicely, and Judgement is a problem solving card. The problem is the Orb. Judgement will solve it (along with most early game enemies and those with thorns).
Mostly though, just pay attention to make sure you're giving yourself consistent ways to hop in between stances and specifically hop into rage mode to get that extra damage, then out so you don't take extra damage.
