yeah! i have some general rules of thumb for improving on lower ascension levels

As you noticed, if you try to force a deck build from the start you're probably gonna have a bad time. Even on lower difficulty levels it's hard to guarantee that you get the cards or relics that you need for any given deck build; the card and relic pool is too large for that, so you kind of have to be flexible.

Here are some unassorted guidelines that might help improve your game which are targeted more for beginners:

Deck execution

The game is not just about deck building! One important differentiator in the success of run is how well you play the deck! Obviously, deciding which cards to play with the given energy you have is important, but there are some other intermediate tricks like:

• think through your whole turn before playing anything

  Sometimes it's tempting to "think out loud" by playing cards as you figure out how to spend your energy, but you should actually wait until you've figured out how you want to play your entire turn before doing anything. Sometimes you can't exactly do that (for example, you might have a card that you can play to draw more cards), but generally you want to think ahead as much as possible before taking any action.

• look at which cards are left in your deck

  Knowing which cards are coming up soon can greatly inform how you play your current turn (even if you don't know the exact order). If you wanna get really fancy you can calculate things like your likelihood of drawing certain cards or sets of cards from your deck, but just looking at the deck at all when planning ahead is already a big improvement.

• learn about enemy move patterns

  All of the enemies have specific rules about the probability of each action given previous actions. For example, a Louse can't attack three times in a row, so if you're fighting a Louse and it attacked the last turn and it's also attacking this turn then you know it's not going to be attacking next turn.

Card picking heuristics

A very very simple card picking heuristic that will get beginners pretty far through lower ascension levels is:

• In Act 1 you should usually not pass on a card reward

• In Act 2 you should usually not pass on an Uncommon or upgraded Common reward

• In Act 3 you should usually not pass on a Rare or upgraded Uncommon reward

  The rationale behind all of these is that (A) you don't want your deck to be too small until you get stronger card draw (otherwise you get hosed by enemies that add statuses to your deck) and (B) you need to be able to take your deck in different directions so having a decent mix of cards provides the raw ingredients to help you exploit card combos when they finally surface.

• You want to diversify the deck

  In other words, prefer cards that make the deck stronger in ways that it's not already strong.

• Avoid the deck becoming lopsided

  Related to the previous point, you want to avoid things like way more offensive cards than defensive cards or way too many powers (maybe ≈1 power per Act as a rule of thumb). Try to keep a nice balance.

• Sometimes the best card to add to the deck isn't the rarest card out of the reward

  For example, many important combos in slay the spire involve common cards (for example: Barricade and Body Slam), so don't be afraid to pick a common if it provides a good interaction with the rest of your deck. You don't always have to chase the shiniest card out of the card reward.

• Avoid obvious bad interactions between cards

  For example, if you're the Watcher you want to avoid adding both Conclude and Meditate to your deck because you can't play both of them within the same turn.

Map routing

One trick I never learned until I started watching streamers play Slay the Spire is that you can look at the Act 1 map before you pick your whale bonus (and it's really beneficial to do so). Looking at the Act 1 map and the upcoming boss fight can really help you pick your whale bonus.

Also, another thing that's not obvious to beginners is that not all "hallway" (non-Elite) fights are equal. In Act 1 the first three hallway fights are easier than the remaining hallway fights and in Act 2 and Act 3 the first two hallway fights are easier. Knowing this comes in handy when picking a route, because you will usually want to plan a route that lines up all those easy hallway fights (but no hard hallway fights) before you first Elite fight so that you have a chance to build up the deck.

Yet another thing that's not obvious is that there are rules to how often potions drop:

Potions are occasionally dropped as a reward after combat. The default chance of a potion dropping is 40% and resets at the start of each Act. If a potion drops, the chance decreases by 10%. If a potion doesn't drop, the chance increases by 10%.

This means that if you're keep tracking of how whether you gained a potion or not after each fight, you know the chance of a potion dropping at the end of the next fight (and you can plan around that). For example, in a fight your potion belt might be full and if you know that you have a high chance of receiving a potion reward from the current fight you might be more inclined to spend one of your weaker potions (even if the benefit is not that great) to make room for the likely potion reward. Or if you know that you've already received a lot of potions (and you used them up already) then you know the next few fights might be more difficult because they'll be a "potion desert".

Elite fights

Counterintuitively, taking Elite fights can be actually beneficial for the deck! For example, if I were playing on the lowest difficulty level you'd probably see me take as many Elite fights as possible (but not necessarily on higher difficulty levels).

When you're a beginner your immediate instinct is to avoid Elite fights because they seem like bad things that you want to avoid or route around, but Elite fights play an important role in the game because only Elite fights drop relics and relics are essential to winning. In fact, one of the harder achievements to unlock in the game is to beat the game without obtaining any relics (besides your starting relic).

Another thing that might not be obvious is that sometimes Elite fights can be easier than the hard hallway fights (the hallway fights after the first few easy ones). The reason why is:

• There is a smaller pool of possible Elite fights

  In all three Acts there are only three possible Elite fights you can encounter and many more possible (10+) hallway fights so it's much easier to prepare the deck for those Elite fights than the hallway fights since there are fewer possibilities.

  Moreover, you can't fight the same Elite fight twice in a row so after the first Elite fight in an Act then all remaining Elite fights for that act can only be one of two fights, which makes them even more predictable and easier to build a deck around. Like, you don't want to overfit the deck to these Elite fights, but knowing what they're likely to be can heavily inform your deck building decisions.

• In Act 1, Elite attack patterns are more predictable than hallway fight patterns

  On lower difficulty levels 2 of the 3 possible Act 1 Elite fights (Lagavulin and Sentries) have deterministic patterns and on higher difficulty levels the same is also true for the third Act 1 Elite fight (Gremlin Nob). You can really exploit this predictability a lot when fighting these elites to beat them by playing your deck around the deterministic move pattern.

  In contrast, the hallway fight attack patterns are typically much less predictable, and this can sometimes make them harder to beat than the corresponding Elite fights.

Estimation

Sometimes you need to estimate the benefit of multiple competing options (e.g. at an Event or Merchant). One way to think about it is in terms of how many net HP that choice is worth over the course of run. Normalizing all decisions to "net HP" can make it easier to compare them.

For example, the +7 HP whale bonus might not seem like a lot, but actually over the course of a run it's worth much more than 7 HP because it affects how much health you also gain at fireplaces or at the beginning of a new Act. If you play through all 4 acts on Ascension 1 then it's actually worth 28 HP + 2.1 HP × {# of times you Rest}, which is really good!

Important decisions

Some decisions matter more than others! Spend more time thinking about decisions that matter more.

For example, the choice of boss relic has a much bigger effect on the run than any given card reward, so it makes more sense to spend more time thinking about which boss relic to pick up; don't rush it.

Similarly, Merchants tend to be focal points for the run, too, especially when you have a lot of gold, so carefully thinking through how you spend your gold at a Merchant is worth taking a lot more time because it will have a larger impact than most other decisions you make.

Also, decisions you make earlier in the run have a larger effect than decisions you make later in the run (because any benefit or disadvantage will compound over a longer amount of time), so you should probably play a bit slower and think more carefully in Act 1 and then you can maybe speed up a little bit as you progress through the game.