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“What if you could change your fate not by changing your actions, but with the actions of others” The state above shows our positioning in how we deal with the time travelling paradox: you can change what your previous units did and is one of the main mechanics in IsoChronous.

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“What if you could change your fate not by changing your actions, but with the actions of others”

The state above shows our positioning in how we deal with the time travelling paradox: you can change what your previous units did and is one of the main mechanics in IsoChronous.

Using time travelling as a game mechanic can bring some undesirable problems. For instance the time travelling paradox known as the grandfather paradox. This was introduced by René Barjavel in 1943 in the book “Le voyageur imprudent”. There, a time traveller goes back before his grandfather gets married to kill him and therefore avoids himself to be born and consequently not being able to go back in time (here the paradox itself).How this applies to the time travelling game mechanic? Imagine that with your current actions you end up modifying what your previous players did: saving the character that you previously controlled from a fatal death. As this is just a game, there are no logic implications that make this impossible, but what we do have are some undesirable consequences.Returning to the grandfather paradox and trying to solve it, we can find different solutions:

  • Restricted action resolution states that laws of nature would make it impossible for the time traveller to modify in such a way that a paradox was created. This approach can be seen in Super TIME Force
  • But another possibility, the one we choose for IsoChronous, is the parallel universes resolution. It supposes the existence of several parallel realities with all the different possibilities for each of your decisions. The basic idea is that when the time traveller went back and caused the paradox killing his grandfather he actually had travelled to another reality in which he kills his grandfather, but in his own reality his grandfather wasn’t killed by him making his action not being a paradox. So time travelling could be seen as travelling not just in the one dimensional interpretation of time, but in the whole plane of the different parallel realities.
  • Yet others exist. For more solutions you can watch the film “Back to the future”, “Looper” or “The melancholy of Haruhi Suzumiya”

The problem with the parallel universes resolution is that implies an infinite number of possibilities for each of the moments that the player could change the behaviour of his previous actions, thing which can be difficult to control (an idea of this was implemented in the game Achron). Let’s try to think a way to limit as much as possible the number of these bifurcations to make it feasible. Why not avoiding the players changing the movements (therefore position) of their previous actions? This implies not changing the walkable map from round to round and not having collision between units. Which are the only states that can be modified now given this limitation? Yes, just the death of the character.How we let the player decide what he did after dying? One solution would be letting him have control of that character again (something proposed in the video “A mind bending gunfight”).

But this would break one of our early game design desicions: controlling just one unit per round so that you can have micromanagement of your units. What we have decided to do is, in fact, an obvious answer: we let him decide what happens after dying just by allowing him controlling the character even if he is already dead. He then can keep controlling a “ghost” version of the unit. This brings even another question: if dead doesn’t stop the player from controlling his unit, what does it? Well, time. Our decisions force us to have a time limit per round which didn’t exist in the case of the restricted action resolution or if we had allowed the player changing between all the current living units (which would be like playing without the game travelling mechanic).

To sum up, when the current unit dies, player keeps controlling a ghosty version of it which will not deal damage in the current round. On next rounds, if the player manages to keep the unit alive, all the actions done as a ghost will affect the rest of units.

Notes: All of our decisions have been taken to provide an easy and tractable strategy through the mechanic of time travelling. Other decisions would have lead us to other games rather than IsoChronous such the mentioned Super TIME Force, Achron or others such as Braid,The company of myself, Recursion, Prometheus, Chronotron, the other IGF entrant of this year Still Time and any of the other games which have dealt with time travelling. It was even this August and September topic (not exactly, it was time manipulation, in fact) inExperimental gameplay project. So experiment with it and see what you can do with it.

Part of the purpose of this post was to research and collect the examples that people has told us since it was surprising discovering how many games (and videos) have used the time travelling mechanic.If you want to learn more, we recommend you these related media:

Innovative Gameplay Using Time Travel and Time Manipulation
Jonathan Blow: Indie Prototyping
How ‘Super T.I.M.E. Force’ avoids the time travel paradox


i like the characters

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Reminds me of Fat Princess. And this is very good.

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