Friday, October 21, 2011

Decisive Victory Updates

I've updated the Decisive Victory rules here to match changes I've made on the DV only blog.

Saturday, October 1, 2011

What it takes to design a game: Part Duex

Last time I talked about my brief history of game design and what pro Ted me to create a WWII naval combat game. This time I'm going to talk about the various design decisions I made.

The first thing I want to talk about is the dice mechanic. I like dice mechanics, such as the one used for Warmachine, that follow a normal probability distrobution. The thing I don't like about Warmachine's dice mechanic is that good results fall on the opposite side of the distribution from the bad results. What I mean by this is: the probability of rolling a 3 is the same as rolling a 11, but the 11 is universally good while 3 is universally bad. So two players can roll results with equal probabilities but it's 50/50 whether one player is having a good or bad day. Basically low and high are the same thing, but one is arbitrarily determined to be better than the other. Drives me crazy.

With that in mind I came up with a 2d6 system that was built around hitting target values from the center of the bell curve. Better results are closer to the center of the curve, and bad results are at the edges. The system gives me the probabilities I want, but it defies the normal convention where one is trying to get the highest or lowest results. I haven't permanently decided if this is the way to go, but for know I'm building the game around it.

I had originally intended for this dice mechanic to be part of a space combat game, and in that system target to hit value where generated by assigning ECM points from your fleet onto your opponent's ships. Obviously that technology is a little advanced, and, with only the US and Brits deploying significant amounts of radar equipped ships in the 1940's, not something that would fit well in Decisive Victory. So I instead built target values off of a ship fire control stat; deceasing the stat according to the distance between attacker and target.

This is where the design gets into the nitty gritty of research and compromise. I spent a lot of time reading to find out what the effective ranges of WWII naval gunfire was. I learned a lot about the capabilities of the technology of the time and the state of naval fire control. It was at this time that I learned about the wonderful US MK37 fire control radar system. It was the fire control system used for US 5" gun mounts and based on technology provided by the UK. America's fast battleships even used a derivative of the system to control their 16" battery. This provided me with one of the first significant design hurtles. The system was vastly superior to anything the axis had. Their fire control systems were optically based and did not directly incorporate radar telemetry even on ships with radar systems installed. This fire control advantage combined with good gun stabilizing systems allowed American ships to draw accurate firing solutions while maneuvering and in a verity of weather conditions.

How do I incorporate this advantage into the game without making the Allied fleets overpowered? I could give the fire control stat a hefty bonus for ships equipped with the system, or I could devise a special rule to allow the US ships to ignore range and environmental penalties. In the end I decided on a stat bonus for radial fire control. I wanted the game to reflect the very specific nuanced details, but not have the player have to worry about them. To that end, I decided to use background calculations to produce stats that took the fine details into account. Special rules can get too convoluted and are harder to compensate for when trying to figure out the nitty gritty balance of the game. This may make Americans very good at long range, but their poor torpedoes should hopefully balance them out.

What to do once ships got hit was another thing I had to think about. WWII had many examples of ships with small guns doing significant damage to larger ships by focusing fire onto the vulnerable superstructure elements. This happened at both Guadalcanal and Leyte, but I haven't seen a ruleset that models that well. So I came up with a system where all attacks that hit do at least minor damage. If a ship suffers minor damage there's the possibility of that damage getting turned into full damage. It's a nice way to model the behavior because I can abstract fire and crew damage as being part of the mechanic.

I also wanted a way to resolve the historical instances where some ships would take tremendous amounts of damage, while others would disappear in instantaneous fireballs. For that purpose, I did away with a traditional max hull points and gave ship a Damage threshold. Hitting the threshold doesn't mean the ship sinks, just that you have to start testing to see if the ship sinks. You roll D6s for every point of damage on the ship; the ships sinking or exploding when you roll enough 4+'s to hit the damage threshold. This adds a little more variability to when a ship will be put out of action and allow for instances where a tin can can fight like a battleship.

Most of the other concepts surrounding damage and armor penetration have been revised through play testing. I'll write another post on the things I've learned from play tests.

Movement was a little difficult to flesh out. This was mostly because I couldn't fin
d any data describing the turn radius of warships. I finally found a document describing the turning characteristics of the Scharnhorst and extrapolated from there. The movement as is I'm not greatly satisfied with. I sacrificed realism for a simpler mechanic. What I have will approximate where a ship will end up after turning for the amount of time in my game scale, but it doesn't get there in quite the right fashion. I may go back and revise it so that the turning circle gets tighter the more time you turn in the same direction. This would be more realistic but slightly more complex to keep track of on the table top.

One of my last initial design considerations was to go for alternating ship activations, and all damage getting applied in the maintenance phase. This was to avoid the "I go first and win" problem games with heavy ranged combat tend to have.

Next post I'll talk about the things I learned from the times I've been able to get play test games in.