ECHO is a third-person stealth/action game with a twist: The enemy AI learns from your actions. Everything you do is recorded by a computer, and after a set amount of time, the enemies in ECHO's world are updated and can now perform any actions that you did previously. However, they don't learn these things permanently. The computer is reset constantly, meaning the AI is continual learning and unlearning new moves as the game progresses.
In ECHO, you play as En. En is a product of genetic modification, making her faster, stronger, and smarter than most. All of this is going to come in handy because in ECHO she is on a mission to bring her friend back from death. So, she travels to an unmapped planet with intel that something there will be able to revive her friend. En also has the help of her own AI ally, London. Together they attempt to work through the palace-like labyrinth, slowly descending deeper and deeper into the planet.
Most of what you will be doing in ECHO is attempting to stealth your way through different levels. However, every action you take has consequences, making levels much more difficult to navigate. Do you want to take the shortcut that will teach the AI how to open doors and use elevators, or should you take the long way instead to try and keep the AI as dumb as possible? This choice is ultimately up to you in ECHO.
Stealth is not the only way that you can get through a level, however. If you find yourself in a pinch, it might behoove you to whip out your pistol and take out an enemy that way. But beware, because that would mean that after the next AI reset, the enemy echoes will be gunning for you from long range, too. In ECHO, your abilities are more your obstacle than your ally.