sorry I cannot resist giving minor suggestions for gameplay mechanisms.
I think mechanisms currently in HSL are really well done already, and they have many benefits (e.g. simplicity). These are just minor refinements.
I'm aware that simplicity is an important feature of HSL, and I don't think these changes would undermine it. Importantly, they no new stat is added, so the rest of the implant (including modding system) is unaffected.
(Edit: I already suggested a few of these in another post. Sorry for the repetition. Here is the polished, refined version of my suggestions, in a thread where they belong.)
Currently any hit landing inflicts 1 HP, even when Armour >= Damage. The suggestion: in these cases there should be
a [Defence - Damage]x5% chance of preventing even that single Hit Point.
Graphics: when the Hit point is prevented in this way, it could read something like "absorbed" (instead of "miss" or "0 Hp"), and make some 'thump' noise. So you know it is your armor which prevented the damage.
Motivation: that 1 HP is annoying because there's nothing the player can do to prevent it (except hoping to be missed, which is not affected by any of his stats). That unpreventable tax can hinder many good strategies, especially for melee characters, which tend to profit on armour. Also, currently rising armour can became irrelevant, which is annoying too.
Variants: the above formula means "rolling 1d20 below Defense-Damage to avoid even minimal damage". It means a 50% chance of not getting damage at all when, say, a rather weak attack (Dmg 10) hits a very armored taget (Def 20), so it is quite mild. The formula can be tweaked by changing the x5 multiplier, and/or removing the "minus Damage" part. For example, it could be a plain and simple: "your Defence value is also the chance of not getting 1HP damage from an attack dealing fewer Dmg than your Defence".
Melee VS ranged:
currently, Ranged (and Magic) attacks work just as well versus adjacent opponents, so basically Ranged (and Magic) is also melee. The suggestion: a Melee character has a [hit chance / 2]% chance of preventing any Ranged or Magic attack fired at him/her from an adjacent square.
Graphics: when an attack is prevented this way, it should read "block" (or "prevent"?) (as now it reads "miss"), and it should make a sound like a failed magic / shot, i.e. as if bow string broke or a magic wand went out of batteries, respectively.
Motivation: when a melee attacker reaches the ranged victim, it should have the upper hand: it had to get there first! This would make melee a bit more comparable, as a strategy, to ranged or magic: ranged/magic players should be more fearful of melee attackers, and melee players should be more at ease once they reached that basta*d enemy archer / magic-user who picked them off from afar. I think it would make ranged feel more like "ranged".
Variants: for extra spice and variation, make presence of a melee weapon necessary in order to prevent ranged attack in this way: i.e., unarmed melee characters cannot prevent ranged attack.
Tune down Regeneration:
The suggestion: make regeneration occur only when the character is attacked but missed, and only if the attack would have dealt any significant damage.
Variants: make a regenerating player regenerate only when it is exploring an unexplored section of the map (a concept inspired by Desktop Dungeon). Leave regenerating NPC as now.
Motivation: currently, with no "errant monsters" and no max HP, a regenerating player can in theory exploit the skill and keep on increasing his/her HP indefinitely, waiting forever before opening the next door. This is being partially prevented by making regeneration occur somewhat less and less often, but this mechanism is not very clear. Either suggested variations tries to be a better and more explicit patch to this overly boring and immediately evident loophole.
Tune down Swift:
currently, a swift character plays twice every turn. The suggestion: instead, give the swift character a random 50% chance of playing the second time. The other 50% of the chances, the turn ends normally at the end of the first play. (keep using the faded icon to indicate, as now, that the player has already played a second time, i.e., that there's no chance of another free move).
Motivation: this makes Swift less overpowered, and also a bit riskier to exploit. For example, a Swift player cannot any longer open tombs with the 100% certainty of avoiding the first strike from the tomb dweller he/she disturbed.
Tune down Shadeform:
suggestion: whenever a character shadeforms into a wall, it loses the next turn (not so when it gets out of the wall into a walkable square). Then, reduce or remove to-hit / to-be-hit penalties.
Motivation: shadeform is currently overpowered. This suggestion would make Shadeform a bit more difficult to exploit in the currently boring but unbeatable strategy to keep shooting at hopeless Melee pursuer, who cannot follow you across walls.