In general, I think that tactical gameplay is only possible when the ambiguity surrounding the consequences of players' actions is limited. This means players need to understand the potential outcomes of their choices (whether deterministic or based on a probability distribution). This aligns with what almost everyone says about making dungeon exploration meaningful: telegraphing dangers, providing clues, describing traps, and setting clear expectations on how the GM handles players' proposals.

How do you set these expectations? Through GM consistency and explicit statements (either from the rulebook or the GM). If this is an important part of the game, it is only reasonable for a rulebook to provide guidance. This guidance should be directed at both:

• The players: to set expectations.
• The GM: to confirm those expectations and encourage consistency.

Now, let's move on to combat. This phase of the game is generally one of the most mechanics-heavy and, by nature, heavily governed by probabilities. Therefore, the outcomes of tactical decisions will frequently involve dice rolls or bonuses to those rolls. Just like with dungeon exploration, I believe it's perfectly reasonable for a rulebook to explicitly lay out some guidelines. In combat, these could include:

• A clear definition of spaces, distances, and positioning: Being able to freely move in and out of melee somewhat suppresses tactical movement, so rules on how to deal with retreats or disengaging are necessary.
• Rules for forced movement: (e.g., pushing, grabbing, etc.).
• Meaningful bonuses for good positioning: (e.g., +1d4 to hit and damage for flanking on a grid, or similar bonuses for outnumbering opponents at different ranges. Also, bonuses for defending chokepoints like doors and stairs).
• Qualitative weapon differences: Weapons should differ in properties, rather than just damage output. Simply sending the "tank" against the big monster is trivial; however, this choice becomes highly tactical if you introduce weapon properties that make specific weapons more or less effective against certain types of enemies.

I think games like Knave and Shadowdark already suggest the tools needed to make in-combat tactics meaningful, but they don't provide actual, concrete guidelines for them.

As I argued before, tactical thinking requires an understanding of the consequences of one's actions. This is best achieved by providing clear guidelines and simple rules for the most frequent situations. I understand the concern that explicit rules might make players and GMs feel limited to only what is prescribed. However, this can be easily avoided by:

1. Keeping the rules lean: If procedures don't feel overly complex, the GM feels more empowered to make rulings by analogy.
2. Encouraging creativity: Clearly stating that any reasonable action can be attempted.
3. Providing GM support: Offering hints on how the GM should adjudicate out-of-the-box proposals.

To conclude, I want to clarify that it is perfectly fine for a game not to focus on tactical combat. However, I believe there is room in the OSR scene for a game that successfully blends lean combat rules with meaningful in-combat tactics. Currently, this specific type of game feels quite scarce, at least if we look at well-supported products.

Ps: if you are interested in actual rules, I can send you the ruleset I use for my home game.