In a militaristic future where mankind has conquered the farthest reaches of space, the crew of a lone research vessel called Antares lies dormant near an off-world mining colony until it receives a distress signal and executes a surveillance mission. Upon descent on the planet you discover that the colony defenses have turned against you. There you must battle the war machines of humanity, now controlled by a sentient entity of unknown origins. As the player, you are the pilot of a space fighter, the only one trained and capable to fend of the enemy forces and defend Antares.


As we are announcing Excubitor's Alpha 0.14 we would like to talk about the problems we've encountered so far. This time we will speak about how we implemented the resources/economy in Excubitor. We will talk about the bad and good choices, and what are our concerns for the future. Hopefully some of you will learn from our mistakes and help us improve the game.

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Hello IndieDB,

For those of you who don't know, Excubitor is a multidirectional shooter tower defense game coupled with lots of weapons, turrets, upgrades and skills. The player pilots the Hammerhead and builds turrets at predetermined platforms. A problem that we had so far is how to implement an economy/resource system which will be easy to use and balance. Even though we didn't expect this to be too time consuming, it proved to be a huge task.


Our first thought/mistake was that one resource would be sufficient for everything. We wanted to cover all the bases: buying weapons, upgrading weapons and skills and building and upgrading turrets. So, everything was good and we decided to name the resource Voidshard (the backstory is for some other time).

The first problem that arose was how the player is going to gain Voidshard. The simplest and safest solution, I guess, would be the player to gain Voidshard as he is playing, i.e., while destroying enemies, buildings, discovering secrets etc. You can see this on the video bellow.

Next we implemented spending Voidshard by building and upgrading turrets and buying weapons. The weapon and skill upgrades were left for later, after we test the concept.


As always you can't see the problems until you are way in over your head. So far, the player can spend Voidshard by building and upgrading turrets in game and by buying weapons in the menu. At first it seemed that it would be easy to balance the game by adjusting the prices of the weapons and the turrets, but if you add weapon upgrades and Hammerhead upgrades in the equation it might become impossible. Additionally you need to account how much Voidshard the player gains per level, which adds another layer to the problem.


After extensive deliberation, the final decision was that if we stick to one resource it would too complex to balance the game. The solution would be to introduce two resources: one in-game and one out-of-game, which divides the balance of the game. Divide and conquer.
The good news is that we can continue using Voidshard as an out-of-game resource, which means a resource for buying weapons, weapon and Hammerhead upgrades, and all the mechanics can stay the same.On the other hand the in-game resource has to be something completely new. The two challenges in front of us are:

  1. How the player is going to spend the resource
  2. How he/she is going to gain it

The resource is going to be spent on building and upgrading turrets and maybe some new mechanics in the future. Pretty simple! Additionally, for easier use we decided to implement a resource pool and call it Power. Each level the player would have a predetermined Power pool for building and upgrading turrets.

The next challenge is how the player is going to gain more Power during each level. The most elegant solution to expand the Power pool is to build Power Generators and spend a little Voidshard in the process. As I said before, the turrets are built upon predetermined platforms, so building a Power Generator would occupy one. The level design had to be changed a bit, because this way we have to have a larger number of Turret Platforms on each level. This is a proof that each new gameplay mechanic propagates throughout the whole game.


Implementing these mechanics brought out new questions that needed to be answered. Building a power generator costs Voidshard. This makes a link between the Voidshard and the Power. The biggest question is if this is going to function properly in the game or just add more complexity.

We don't know the answer! That's why we are sharing the latest build of Excubitor with you.

If you have any suggestion please share them in the comments bellow.

Until the next post stay frosty and good gaming.


Excubitor Alpha 0.14 - Windows


Excubitor Alpha 0.14 - Linux


Excubitor Alpha 0.14 - MacOS


Honestly, I find this change a good one, I think it adds more strategic depth to the placement of your turrets and generators. What if the enemies targeted your generators and turrets? (unless they already do) I think that might add more strategic elements to the game...

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TesseractInteractive Author

For now the enemies don't target the turrets or generators but they do attack the player. Enemies act pretty much as in most tower defense games, advancing towards the defense location. However we discussed the possibility of enemies attacking the turrets, several times now, and it's something we wish to try in the future.

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