Posts Tagged ‘Gameplay’

Shoot the Critic – Design by Critical Averages

Friday, July 23rd, 2010

Design a game, and you are bound to find plenty who don’t like it. They might hate the art style, or the gameplay mechanics, the story or the cutscenes. Now you can take your game and respond proactively to criticism by adjusting the design. Little by little it will transform into a bland average of the favourite games of your critics. To improve game design you can’t just clip back all the bits the critics hate – no, you have to carefully prune and nurture them into something worthwhile.

Shoot The Critic

I’ve been working on mission design this week, starting with the simplest of mission types: Goto, Fetch and Kill. If you listened to the critics bashing these simple missions in RPGs and MMOs you would think that players hate them with a passion and yet they provide the basis for generation after generation of game. There is certainly a strong critical emphasis on boring, pointless and repetitious quests that are necessary to advance. But what would these games be like without mirco-quests to encourage the player to roam, fight and explore? Well, probably a grind-fest on random encounters between boss battles. But the situation is not much improved if questing itself becomes a grind activity.

However as the care taken over these quests increases, when they become integrated into the larger gameworld, more complex in length and twists, and most importantly of all if they offer choices of how to achieve or even rebel against the quest goals – then they they can become an enriching part of the game rather than a cynical length booster.

Another alternative is to clearly mark the micro-quests as optional activities, and let the player choose to use them as an opportunity to advance. For example in role-play Sim games you often have to choose what activity your avatar takes each day, and the choice will result in a fairly predictable outcome of money or stats improvements. The choices are the same each day, and it becomes more of a meta-strategic game choosing a good mix of activities than a test of how well you perform each task.

In Spice Road, there are three kinds of mission. The first is a veiled hints system – so if you are bewilldered by the scale and opportunities available in the sandbox, the hint mission will find you a suitable trade route, or exploration area – nothing you couldn’t have done on your own, but adding structure for those who need it. The second covers reactive and progressive missions to protect and advance your companies towns and trade routes. For example, if a bandit camp is reducing the safety of one of your caravan routes a mission is generated after a caravan is lost urging you to seek and destroy the bandits. Or if your building requires a skilled workman to progress a mission might spawn to help you find one. Lastly there are tactical missions to progress the causes of the nations and guilds. These are more complex nested missions trees that offer useful rewards in the way of new units, skills and access to new parts of the map – however you must pick your allegences carefully as many missions are at the expense of other factions.

Fortunately as a true sandbox, you are not tied to any set of missions and can achieve the same results through your own cunning, persistence and might. The missions are there to compliment the gameplay.

Desert Trading Simulation Game

Saturday, July 3rd, 2010

Spice Road features trading as a game mechanic. The desert wilderness is surrounded by fertile and industrious nations who want to share their varied goods with each other. You can make money by trading goods from producing nations where the price is low to consuming nations where the prices are higher. You can also trade in-between making the most of local price gradients and fluctuations in the desert and mountain outposts.

As well as goods like silk and spice, you can also take people into your caravan – pilgrims, travellers and slaves all can make goods returns for safe passage.

Once you have picked a profitable item to trade you should examine your route carefully. If the destination is a long way away it is a good idea to find a oasis or tradepost along the way to restock on water and supplies. Your party design depends on your route – a long desert travel will benefit from hardy camels, while  a run through northern foothills would need some soldiers in your caravan to ward off bandits. The further you have to travel, and the more support people are in the caravan the more supplies you will need to take – reducing your capacity for profitable goods.

Finally you can stock up on the goods themselves – and hopefully a few months later… Profit! Unfortunately there are many dangers on your way so you better look sharp and think fast to adapt to whatever circumstances are thrown at you.

Once you have become a skilled trader you can train others to run caravans between Trade Houses you build in different towns. This also has the effect of improving your relationships with the towns and expanding your network of information. Complete networks of trade routes from production to the final consumer are a fine accomplishment that earn you respect and great wealth.

On the shady side of trading – some goods are frowned upon by respectable authorities. If you want to sneak opium or weapons through a controlled land you will have to be fast and inconspicuous. A small mounted party is fastest, but avoiding guard posts will lead you into hostile bandit lands.

Trading in desert lands with bandits and caravans has never been so much fun.

Difficulty Curves in an AS3 Defence Game

Saturday, January 30th, 2010
Slice: Fortress Defence

Slice: Fortress Defence

How hard is a wave of enemies? If the enemies get twice as strong as the player gets twice as strong there is no change in difficulty. The difficulty of a defence game is related to the ratio of power between the enemies and the player. Over time the player buys upgrades and gets stronger, and the strength of the enemies must match that closely to make the game challenging, fun and progressively more difficult.

My original plan for Slice: Fortress Defence was to tie the important variables to math equations like so:

Enemy Power: Linear Growth

Gold per Wave: Linear Growth

Unfortunately the linear gold drops resulted in polynomial player buying power, as each wave added to all previous gold spending (and so power increases).

Player Strength = Gold per Wave + Gold for all previous Waves = Area under Gold per Wave graph, approximately (G^2)/2

Player Strength: Polynomial Growth

Polynomials always grow faster than Linear in the long run – so this would leave the game hard at the beginning but getting easier and easier as the player upgraded. That’s no fun!

So I moved to an exponential model. Exponentials have an interesting property whereby the sum of an exponential is also an exponential – this makes balancing the ratios much easier!

Enemy Power: Exponential Growth

Gold per Wave: Exponential Growth

Player Strength: Sum of Gold for all Waves => Exponential Growth

By making the Enemy Power exponent slightly larger than the Gold Exponent the ratio of Enemy to Player power would also follow an exponential curve – and thus the difficulty would rise slowly then start ramping up fast at the end of the game.

Now all I had to do was ensure my units Purchase and Level Up costs gave a good ratio of Power to Gold. Three factors effect unit power: Damage, Range, Rate of Fire. All three must be combined to give a single Power rating to match to balance against Gold – I just multiplied them together, so a 10% rise in all three would give a unit 33% more powerful, and consequently it should be 33% more expensive.

With a little tweaking this system could now produce defence games of any length by changing the Enemy Power and Gold exponents.

In actual fact – once I had a Power to Gold ratio I could calculate the Players total expected Power from the Sum of all Gold Spent – so I uses this expected power to generate my Enemy wave power. This keeps the enemy and player in close step without getting bogged down in maths.