Into the Breach is set in the far future where humanity fights against an army of giant monsters collectively called the Vek.

The gameplay of Into the Breach has been compared to that of chess, as it is less about overpowering the opposing forces and instead about maintaining position control and sacrificing units to gain a larger advantage; this comparison is further enforced by the grid structure of combat scenarios, where fights are broken into 8x8 squares.

[3] Should the player lose any scenario, either due to their three mechs becoming disabled, losing their power grid, or failing to protect a specific target for that scenario, then the player has the option to send one of the pilots back in time prior to the start of the first mission – effectively starting a new game – retaining their current experience and abilities to give an edge in the next battle.

[3] Reviewers for the website Rock Paper Shotgun described the gameplay as a mix of Pacific Rim and Edge of Tomorrow due to the time-traveling elements.

This came as a response to films like Man of Steel and Pacific Rim, where "the whole city gets demolished, but no one cares because the good guys won", according to Ma.

[2] They set about to make the game focus on the impact of collateral damage so that defending buildings and other structures would become a priority rather than just winning.

[2] Subset included the effects of giant mechs-vs-giant alien battles on the landscape as the game time progress, with mountains being torn down, forests destroyed by fire, and buildings razed.

The limited turn counter was used to keep battles short, and Subset found that telegraphing the Vek's movements further helped to hasten the pace.

[2] Development of Into the Breach started mid-2015, after all of Subset's commitments to FTL were completed, providing them with the financial security to move forward onto this project.

[7] In addition to the digital score, Prunty added some guitar riffs atop the music, creating a motif that appeared throughout the tracks.

[11] A free Advanced Edition update to the game was released on July 19, 2022, for personal computers and Switch versions, adding more content including new squads, pilots and enemies, and an "Unfair" difficulty level.