If we’ve learned anything from Back to the Future, it’s that when messing around you need to avoid causing a paradox at all cost. Developer Capy Games has been experiencing this problem first-hand while designing Super Time Force, a side-scrolling shooter where death sends you back in time. Since multiple past version of yourself are on screen at the same time, what if your present actions accidentally change your past’s fate? “It’s not really an issue you can solve,”  lead programmer Kenneth Yeung told The Verge, “it’s just something you have to design around.”

One way they worked around the problem is by giving the enemies have preset behavior. This way, enemies will act the same way every time, preventing their behavior from changing and possibly causing a paradox. All moving and interactive objects function in ways as to avoid paradoxes as well.

“Maybe the next time you play you get there a bit sooner and the enemy will aim its gun at you and shoot bullets there. The problem with that is if you got there sooner there will be enemy bullets that exist in the timeline at a different time than they existed in all the previous timelines, which could result in guys dying.”

Time travel will also be important to the story, although there is not as much pressure to avoid paradoxes as in the gameplay. As writer Dan Vader explains:

“All the stuff that you read about in science journals or time travel fiction that gives you a headache just to try to wrap your mind around it, actually crops up when you’re designing the day to day level stuff, as well as the story.”

The concept of time travel can be hard to wrap your head around, but Capy Games seems to have a great handle on it. “It’s this ongoing design challenge to make sure that time paradoxes don’t happen,” says Yeung. While confusing, the concept does have one huge upside: “Time travel gives us the liberty to do whatever we want, go wherever we want, encounter whatever the heck we want.”

Source: The Verge