If you watch people playing your game you can observe some common behaviours  These have been developed in our minds due to several years of experience with games and human-interaction which have led us to well established gaming and interaction concepts/behaviours. One of these well established concepts is death: if you die, you start again. But what happens if that doesn’t apply to your game? Well, you are in trouble if you don’t communicate them properly to your players. In IsoChronous we introduced some mechanics that broke with well established concepts in games. Bellow there is a list of these mechanics and how we tried to deal with them in order to make them enjoyable and understandable.

The ghost mechanic or explaining the player that even dead he can continue moving and attacking but not being able to interact with the rest of the units in battle (you can read more about the ghost mechanic here). In most of the games, when you die you have to wait to start again, but not in our time-traveling game IsoChronous. To amend this problem we decided to use the obvious metaphor of it: being a ghost, that is also what other games have used (World of warcraft, Dark Souls, Soul Reaver). The problem we encounter is that most of the mentioned games also modify the look and feel of the environment giving like some sort of implication of “ghost view”. This visual reinforcement sure helped them but it was not suitable for us since both players are sharing the same screen (it could be applied for an online mode, but we prefer the “offline” mode, where the 2 players are together and can see, yell and smash each other).

Right now we decided just continuing with the individual ghost metaphor by doing an explosion followed by a grave that comes out and converting the player into a ghost:

The problem is that we have experienced that some of the new players either don’t realize that they are dead or they stop moving when the character dies. We introduced even more details apart from the mentioned ghost appearance, to reinforce the idea: we disable the gamepad vibration that happens when you are alive and you deal damage to another unit, the thrown projectiles don’t collide with the environment as they do when you are alive…

Finally, to address the problem of people that stop playing when they are dead we make a message pop out and blink when the dead player keeps his unit immobile.

Time rewinds at the end of each round. In most of round based games when one round finishes the next one is completely new but in IsoChronous when a new round starts the previous actions already have effect in the world. We represent this fact with the time travelling  but we could have used any other metaphor like saying that each unit was some sort of robot that recorded what it did and repeated it again and again. We chose the time travelling explanation because is easier to represent graphically, and we wanted the player to discover the mechanic by himself without many textual help. To make more clear this metaphor, we added a rewind effect similar to Braid (either visual and with the music) with some visual reinforcements (clouds on the ground of the island and the mid river which go backwards when time goes back in order to help the player understand that time is rewinding).

Now the problem was letting the players know that the previous units would repeat what they did and that they were not controllable any more, since in most of the games where you have several units playing you can change between them (either just having one of them at the same time in the battleground like in Tatsunoko vs Capcom or having all them like in LEGOs or RTS in general). What we did was to lower the contrast of the previous units as well as putting a marker on top of the current unit. Also we kept the previous units in front of the tower and when the new round starts you can see how to new unit comes to the battlefield while the others are still there. All this to emphasize that the current units and the previous ones are not the same. Other things we tried were some footsteps that appeared in front of the previous units advancing its nexts movements and giving the feeling of being following a path (the one recorded when you controlled it), but we had to remove this as it was more chaotic and confusing than helpful.

Rounds vs time layers or wining a round doesn’t makes you win anything. One of the things that we wanted to change in IsoChronous is one of “problems” in having rounds: imagine that you are battling to the best of 5 rounds and you have lost the first 2. This situation, depending on the person, can provide a feeling of despair since you have to beat all the next 3 rounds without failing. As stated, depending on the person this can be seen as an extra motivation to do your best but we wanted to experiment and see what happened if we tried to change this by making only the last round the decisive one,  removing all feeling of despair (if you lose firsts rounds it doesn’t matter because you can change the results in last round and also if your unit is defeated in the current round you can continue using it so you are never useless). The first problem we saw is that if you use the term “round” players directly imply that the one of them who wins more rounds is the final winner. To prevent this we had to come up with a different word when we wanted to refer to rounds, so we decided to use “time layer” instead as this was a new concept that attracts the player’s attention and helps them understand the game. Also it helps to explain the time-travelling thing: you add a new layer to the existing battle so all rounds happen at the same time-lapse (that’s where the name Iso (same)+Chronous (time) comes from))

There are plenty of well established concepts and interaction methods in players minds and dealing with ones that break with them or provide new ones can bring some extra design problems, but at the end this is worth it, either for the developers which will have to think and deal with problems that help them improve, but also for the player which will be thankful to see something that defies and presents new concepts. Because at the end is by dealing with new concepts that we learn the most and experience a richer and more stimulating interaction. Good examples that experimenting and trying to break classic mechanics is beneficial include interesting games like: Braid (different interactions with the space-time), Journey (non verbal communication between players), The marriage (games as art), Miegakure (exploration and understanding of 4D spaces), Bara Bari Ball (8 jumps instead of the typical double jump), Storyteller (storytelling as a game mechanic), Johann Sebastian Joust (no-graphics game), SpyParty (detection of human behaviour) and Antichamber (exploration of non-Euclidean spaces) to mention some of them.

“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) in Experimental 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