The gameplay is similar to Crusader: No Remorse. No Regret added several new weapons and death animations, including freezing (and subsequent shattering) and two different kinds of melting. In No Remorse, the Silencer could carry no more than five firearms at once; in No Regret, this restriction was lifted entirely, along with money.
No Regret begins 46 hours after the events in No Remorse. A WEC freighter headed for the Moon picks up the escape pod, and the Silencer, upon moonfall, makes contact with the local Resistance. The WEC uses the moon as both a mine and prison, where most of the political dissidents and Resistance members are forced to extract a precious radioactive compound, Di-Corellium, the mineral that is the basis of virtually all energy production on Earth. Approximately half of all known reserves are on the Moon, and a shortage of Di-Corellium would cause serious problems for the WEC. For this reason, Chairman Draygan is on the Moon to oversee the Di-Corellium production, which has been lagging recently—possibly due to incursions from the Resistance cell on Moon, at the hidden Dark Side base. He is, to say the least, not happy when he learns that the Silencer appears to have survived and may well be on the moon.
Over the course of No Regret's ten missions, the Silencer works to undermine the WEC presence on the Moon, culminating in a showdown with Chairman Draygan who pilots a mech. The WEC's lunar headquarters are destroyed and the Resistance takes control of mining operations, with the hint of further conflicts with the WEC. The game's story is notably more simplified and straightforward than that of No Remorse.
Both games use an advanced version of the Ultima VIII: Paganisometric view engine featuring full SVGA graphics. The game's audio uses a specially made engine, called Asylum Sound System, which employs MOD files rather than General MIDI, in order to provide good quality without relying on expensive hardware. Each mission and intermission level has its own track. The soundtracks for both games were composed by Andrew Sega and Dan Grandpre of the now-defunct Straylight Productions.
The Crusader games feature full motion video (FMV) sequences with live actors; FMVs are used in cutscenes to further the story, generally through interaction with other characters. These conversations are generally one-sided, as the player character never speaks. Like many Origin games, both No Remorse and No Regret shipped with significant in-universe back-story material, including a fold-out propaganda poster, newspaper and guides from the WEC and the Resistance.
A working title of Crusader: No Regret was No Quarter and Origin management also wanted to release it as Crusader II: No Regret. A cancelled multiplayer expansion was titled Crusader: No Survivors.