As mentioned previously, my main goal was to reduce and simplify the math as much as possible. Considering how slightly varied damage output, hp, buildup damage, etc can be for machines and Aloy in the video games, it was quite a challenge to roughly keep the same feel of variety and difference, but reduce the number game by quite a bit.

First Steps

I started by writing down every machine's HP as can be found in Horizon Forbidden West. This ranged from 95 HP for a Burrower to 11'250 HP for an Apex Slaughterspine, which is quite the difference. The first challenge was to reduce the HP as much as possible to a much more manageable number but roughly keep the difference at a level that feels right. 

This led me to write down average damages for all sorts of standard common weapons, from the different Bows to the Blastsling and eventually Shredder, etc. I then calculated how many attacks it took to bring down two different machines as examples I took the Burrower (95 HP) and the Thunderjaw (6'500 HP)

With the weakest Hunter bow only dealing 15 point of damage, it took about 6 hits to kill a Burrower and 433 to kill a Thunderjaw, once again, quite the difference. I then tested around with various damage models, rolling for damage with different dice, only d6's with and without modifiers and just fixed damage. Since the Idea is that killing a Thunderjaw will take some time and thus multiple rounds, I decided to go against rolling the dice, this allows players to always know how much damage they deal and only resistances, weaknesses and critical hits can either double, quadruple or half the damage. Reducing the math required immensely as each damage output could possibly be written next to the normal damage output.

I then tried to keep the number of attacks needed to hit and kill a machine at lower levels roughly the same. The more threatening machines obviously had to be reduced by quite a bit, but they were still dangerous enough and not too high in HP to become overly complicated. This ended in a standard Bow dealing 2 damage, against a Burrower that will still be about 6 successful hits to kill, while against a Thunderjaw it was now reduced to about 55. All of this still requires some playtesting, if the Thunderjaw seems too weak at higher levelled equipment and player characters, then some adjustments need to be made.

Appearance and Design

One big aspect of ttrpg's is how a Character sheet or a monster statblock is designed, what information is on there and how useable it is. Since Machine HP will stay the same between the same types, I decided to present the HP in a slightly different way. Instead of a field with a number, it is 2 or more rows of squares (or triangles as it ended up being). this allows the GM to simply fill in the triangles with the amount of damage dealt, reducing the math and simply making it a counting job, which hopefully increases the accessibility and useablity.

This automatically led to another function of injury levels. Which does not but can affect the players and will affect the machines. The player's HP is still done by writing down the number since the HP regularly increases through levelling up.  I am still thinking on a design which could benefit from the same functionality as with the Machines HP, despite the everchanging maximum HP.

Dice Math

As I already talked about in the last Horizon-Log. The dice system is a successpool, rather than a summed max number rolled. This simply has the reason to also reduce the math. Instead of rolling 2d12 and 4d6 to get a number range from 6 to 48 you can now have between 0 and 6 successes.

Conclusions

Not only did I make this change for easier accessibility, but since not every person is very good at mental arithmetic, myself included, I am descent, but at higher numbers, I do take some time.

Time is the other aspect which I wanted to reduce. As mentioned previously, to take down a THunderjaw, you must hit about 55 times with a standard bow, and that is if every attack hits. For a group of 5 players, this is reduced to 11 turns if every player hits with their attack. As you can see, the number of rounds per combat can increase drastically, which is intentional. A player is supposed to possibly run out of supplies and especially ammunition in a difficult fight, forcing them to make some decisions before or during combat. To not have combat, which has 15 or more rounds that take hours upon hours to complete, I decided to reduce the math as best as I can and simplify the process of taking and dealing damage, to hopefully quicken a player's and Chaplain's (Game Masters) turn.

There are other aspects which I try to implement or leave out to reduce the amount of time it takes for a player to take their turn, especially by reducing the amount of actions a player can take or simplifying features such as Valour Surges to be easily understood. Since Horizon does not deal with magic and spells, the most complex aspects might be the Techniques, Valour surges and various weaponry. But it is still, hopefully, immensely reduced in complexity compared to some spells in a Fantasy TTRPG.