Time travel is a tricky thing to implement in a video game, especially when it fundamentally affects the title’s play mechanics. What if time travel is not only an active part of play, but its use constantly changes the game’s experience? Independent game developer Hazardous Software is figuring out the answer to this question with Achron, a real-time strategy game that requires players to think in four dimensions instead of three.

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This is a very smart game, involving some extremely advanced concepts based on real theoretical physics. Case in point: aside from incorporating time travel into the strategy, players will also have to account for the paradoxes that result from sending units through the fourth dimension.

Let’s say you decide to take the sneaky route and destroy an enemy’s factories in the past, thereby nullifying the armies they have in the present. However, before a time wave (explained later) reflects the changes in the present continuity, your opponent manages to pull the same move with you. This creates a paradox: both players’ units shouldn’t be around in the present, but each result will periodically dominate the present timeline when a time wave hits the present timeline, canceling out the other; the outcome oscillates between each player’s favor.

If you’re advanced enough, you can time out the time waves’ patterns so the events work out for you. Paradoxes in Achron are resolved when an event falls off the observable Timeline, thereby locking them into the level’s permanent continuity.
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For an indie game that’s in an alpha release, Achron looks pretty good, albeit a little simple. At the same time, it’s incredibly stable and the gameplay is very solid. As I worked my way through the demo levels that are available, I found myself replaying many of them so I could understand how to use teleportation nodes and time travel better. It was somewhat difficult to grasp at first, but it was interesting and became a ton of fun to play with once I got the hang of it.