One or two players traverse procedurally generated levels across several stages set in the mind of Mental, the antagonist of the Serious Sam series.

The game received mixed reviews, with praise for its humour, art, and combat, with criticism towards technical issues, repetitiveness, and lack of innovation.

Chests provide three random upgrades to choose from, while shops require the spending of the currency obtained by defeating enemies.

[5] Over time, the player collects thirty-two black keys used to unlock power-ups in the vault that occurs after completing all stages once.

Additionally, Croteam's Roman Ribarić, Andrej Smoljan and Damjan Mravunac acted as producer, sound effects artist and composer, respectively.

[9] As the expanded team was unhappy with Spitfire Inferno's theme, Ribarić suggested that Gungrounds shift the game to the Serious Sam universe.

[8] Tormental was due to be launched in Steam Early Access in August 2018 but was delayed to allow for quality assurance and the completion of some existing features.

[17] The early access version, now renamed Serious Sam: Tormental, was launched on 2 April 2019 for Windows, with Croteam Incubator acting as the publisher.

[20][21] The game was initially intended to remain in early access for 6–12 months, depending on player feedback and prospective further features.

[9] Upon the initial release, Gungrounds announced a shortened prospective period of 2–3 months, though noting that it could change based on internal milestones.

[4] KC Nwosu, in his review for The Escapist, similarly enjoyed the art style, which he believed fit the series better than those found in other entries.

He regarded the movement and shooting mechanics as "adequate" but lamented that obtained weapons and upgrades "never reach the necessary level of absurdity to excite players to go another run".