The player takes the role of Ein, a Grim Angel, who must battle against demons as well as antagonistic Grim Angels to seal away the four fountainheads of evil known as the Accursed. He is accompanied by four heroines—Fia, Lina, Serene and Cierra—as well as his cat-like familiar Rose. Riviera also contains dating sim elements, as the hero can achieve multiple endings with the supporting characters through decisions made throughout the game.
For each of the seven main chapters of the game, the player starts in Elendia, and is given a mission. The player then moves on to wherever that mission takes place, proceeding through nine stages, to the eighth stage which will contain the chapter boss. The ninth stage is secret, and often has a particular method of infiltration. Within each stage are multiple screens, all with events and battles of their own. When a chapter is completed, all trigger points currently accumulated are erased. The player is taken to a results screen showing how they performed in the chapter, and gains trigger points based on that performance that can be used in the next chapter.
Once all the preparations are made, battle begins. Turn order is decided by a countdown based on agility, last move used and formation. A player character may select from as many as eight different skills: one normal skill for each item, and, if they are well trained with that item and the OverDrive Gauge is sufficiently filled, a secondary, more interesting OverSkill. Using a skill, however, reduces how many more times that item can be used, as Riviera employs a Fire Emblem-styled system of item endurance allowing the item to be used only a certain amount of times before it breaks entirely. The OverDrive Gauge fills throughout battle, as characters receive and deal damage, and with certain skills. At various levels, characters can use different skills, because certain skills require more of the gauge be filled. There are five levels of skills for player characters: Level 0 skills that may be used whenever and without training; Levels 1 through 3 skills, which require training and deplete that amount of the OverDrive Gauge; and Execution Level skills that may be used at any level of OverDrive Gauge fullness, but will shatter the gauge for the battle, and are only obtained through the story. Enemies have a similar gauge with three levels: Normal, Rage and Max. At Normal they may only use normal attacks. At Rage they may use Rage and Normal attacks, but the latter depletes the gauge. At Max, they may use all three, but only Max skills will deplete the gauge, and will deplete it fully. Enemies also have Etc. attacks, ranging from healing to transformation, that may be used at any time.
Once all allies have had their HP depleted to zero, the battle will end triggering a Game Over, which will give the player the option to retry the battle with the enemies' stats lowered and the OverDrive Gauge filled. If all enemies have had their HP deplete to zero, instead, the player will achieve victory and receive a rank based on their performance in battle. The rank is based both on time spent in battle and the finisher, but the rank will also be lowered if the player retried. Trigger Points and items are distributed based on the rank the player obtained in the battle. Also, if a character used an item enough times, that character will be rewarded with a stat up and the unlocking of an OverSkill that can be used in later battles.
Riviera: The Promised Land draws from diverse mythologies, most prominently Norse, where it incorporates concepts like Ragnarok and Yggdrasil into its story. The game takes place mostly on the continent of Riviera, with the characters visiting various locales such as a sinking city, a forest, and an abandoned cemetery.
Riviera offers a cast of six playable characters. is a Grim Angel, who sacrificed his black wings in order to receive his Diviner, Einherjar. He wears shorts, a vest, gloves, a cape and a scarf; he has grey-black hair and deep blue eyes. He appears to be an average teenage boy and is quite naïve, an attribute that annoys both his partners Ledah and Rose. is a teenage girl with a caring personality. She wears a long green skirt, and a black vest over a long-sleeved white blouse. She has long green hair tied with a matching ribbon and green eyes. Originally, she shared a house with Lina, but later made room for Ein, Cierra and Serene. She is, like Ein, kind and noble, sometimes stern and serious and she can cook and mix herbs well. She is extremely mature, despite being the youngest of Ein's four female companions. Sometimes Fia shows signs of shyness toward others, especially Ein, for whom she nurses a soft spot. is a sweet, childlike and energetic teenage girl. She wears a flamboyant yellow short-skirt and overcoat. She has brown eyes and orange hair tied into pigtails. Lina enjoys eating, going on adventurous treasure hunts and playing lively games with her friends; she is ignorant about household chores. She constantly gets into situations in which she embarrasses herself, especially around Ein, for whom she hosts a secret infatuation. is an outgoing, tomboy-ish teenage girl, the same age as Ein. She is an Arc, unlike the majority of the inhabitants of Riviera, who are Sprites. She used to live on Rosalina Island with other Arcs until her entire tribe was killed by the Grim Angel Malice. She alone survives and joins Ein, for whom she develops an infatuation. Serene has large, batlike wings, a trait shared by Arcs. She wears a helmet adorned with a pair of fake cat ears on her shoulder-length dark blue/indigo hair and has blue eyes. She wears a long pale blue vest over a black body-suit and a dark blue shawl. is a kind, thoughtful witch. She is the older sister figure of the group and possesses amazing magical powers. She is always optimistic but sometimes clumsy. She rescued Rose after she and Ein were separated, although she accidentally fed her a potion that removed Rose's ability to talk. For enjoyment, she studies and plays with magic. Cierra wears a typical witch's conical hat, red boots, and a revealing, serrated red dress. is an experienced warrior and one of three Grim Angels shown in the game. He is a strong, loyal, and very solitary man. It is suggested that he is much older than Ein and his companions, given his experience, and the choice of voice actors for him in the GBA and PSP remakes but this is debatable. He follows the order of the seven Magi without question. This is because he traded his emotions for his Diviner, Lorelei, preventing him from reconsidering the orders given to him. Except just before dying, Ledah is shown as aloof, cynical, and pragmatic.
The above characters are the only playable characters in the game. Riviera has several dozen supporting characters, notably Rose (Ein's familiar); Hector (the game's villain); Malice (Hector's henchwoman); Ursula, guardian spirit of Riviera; and the Four Accursed, who act as Stage bosses. There are also numerous Elendian citizens, fairies and undines who help Ein along the way.
A thousand years before the game takes place, a war known as Ragnorok took place. The gods of Asgard were attacked and overrun by demons from Utgard. In desperation, the gods broke an ancient covenant; they sacrificed their lives to create black-winged reapers that came to be know as Grim Angels. Each was armed with a "Diviner", a sacred weapon with which they easily vanquished the demons. After the war ended, Utgard was renamed Riviera and turned into a beautiful paradise. The gods left their knowledge and authority in the stewardship of seven Magi and their power in the care of the Sprites, the inhabitants of a peaceful Riviera.
After a thousand years of peace, rumors of the demons’ return surfaced. Hector, one of the Seven Magi, sends the Grim Angels Ein and Ledah to Riviera, accompanied by Ein's familiar, Rose. They are ordered to activate the "Retribution", a hidden power of the gods which would eliminate the demons but destroy Riviera in the process. At the end of Heaven's Gate, they meet Ursula, the guardian of Riviera. Ein falls in battle and is taken to Yggdrasil, the heart of Riviera, by Ursula. Discovering that he has a good heart, she entrusts him with the protection of Riviera.
Ein wakes up suffering from amnesia and able to recall neither his purpose nor his origin. He is nursed by Fia and Lina, residents of Elendia, which is a village near Yggdrasil. News about the rebirth of the "Accursed" - the "progenitors of evil" - reaches them and they set out to investigate. Eventually, they defeat all four and meet Serene, Cierra and even Rose along the way. Meanwhile, Ledah searches for Yggdrasil, so that he may activate the "Retribution".
Ein now expects to live peacefully in Elendia with his new-found friends, but Ursula informs them that Ledah has breached Yggdrasil and intends to destroy the three "Aquariums", the sources of Yggdrasil's power, in an attempt to activate the Retribution. The six companions (Ein, Lina, Fia, Serene, Cierra and Rose) head out to Yggdrasil. Although they manage to subdue Ledah in battle, it is the Grim Angel Malice, Hector's pawn, who deals the fatal blow. A dying Ledah warns them that Hector has tricked them all this time: he does not fulfill the will of the gods, but seeks ultimate power for himself.
They pursue Malice, but are unable to prevent her from destroying the last Aquarium. They battle her, and eventually Ledah appears to intercept one of Malice's attacks. Ledah dies soon after, telling Ein to stop Hector. The companions then race to the "Maze of Shadows" where Seth, the Sealed One, is imprisoned. There, Hector takes the life of Malice and the girl that Ein has become closest to; the last two souls required to unleash Seth. Hector intends to become the one True God, and to this end he fuses his body with that of Seth to become Seth-Rah. However, Ein and his companions are able to defeat Seth-Rah, and afterwards they are teleported back to Yggdrasil by Ursula just before the entire Maze collapses.
Upon their return, Ursula reveals that, with the death of her counterpart Seth, she too will cease to exist. Before disappearing, she resurrects the girl that Hector killed, and also charges Ein, Fia, Lina, Serene, Cierra and Rose with the continued protection of Riviera.
Since Riviera is a renai, the player can achieve multiple endings depending on his responses to his companions. Depending upon them, an ending may be achieved with Ein and the girl of choice having a special scene together. The ending with Rose is a hidden ending, as it was not in the original WSC game, and Rose doesn't have a trust stat in the game. The last frame also tells (no matter what the ending) that Rose becomes a historian in later life and records their adventures.
Another Dept. Heaven title, Yggdra Union had an effect on the following PSP remake of Riviera. Artist Sunaho Tobe is quoted as saying that in the CG image for the Archangel, she drew inspiration from the designs of Yggdra Union.
The Japanese voice actors and actresses for the Japanese PSP version are largely the same as the GBA version, featuring Rie Kugimiya as Ein, Masakazu Morita as Ledah, Rika Komatsu as Rose, Hiromi Konno as Lina, Natsumi Yanase as Fia, Ai Nonaka as Serene, and Yuko Goto as Cierra. Atlus USA, as they often do, chose to keep the Japanese voices in their localization of the game, as well as add English voice work. However, this led Riviera PSP to having the clunky requirement of choosing the language of voice acting every time the game was loaded. The English voice actors for the game are largely unknown due to Atlus' tendency to not release cast lists with their games, though many of the GBA version's English voice actors returned for the PSP version's localization.
The soundtrack for Riviera was composed mostly by Minako Adachi, with a few tracks by Shigeki Hayashi, and spanned less than forty tracks. This music has been rearranged and rerecorded for each release of the game, but has for the most part remained static. The soundtrack has been released twice, with the first following the GBA version's release, the Riviera Full Arrange Soundtrack, which featured arranged versions of all the songs, but not the original GBA or WSC versions. Soon after came the "Riviera Intro Disc" which featured the WSC music, as well as a Drama track introducing all the characters. In February 2007, following the release of the PSP version of the game, Sting released the Riviera Perfect Audio Collection Plus, a three disc collection containing the original music from all three versions of the game.
Sting has also released several drama tracks for Riviera, the first appearing on the Riviera Intro Disc, followed by four on the Riviera Epilogue Disc, and then a full-blown Drama CD following weekly airings on used to promote the PSP version. This Drama CD was called The Precious Chapter and contained seven drama tracks spanning two discs.
Riviera: The Promised Land generally garnered fairly positive views, with Game Informer giving the Game Boy Advance version 8.25 out of 10 and GameSpot giving it 8.7 out of 10. 1UP described the game as "the most streamlined RPG imaginable". Praise went out to its gameplay design, in which allowed conversations to occur frequently and smoothly. 1UP, however, also claimed that the experience and item systems were "a bit damaged" and "slowed the pace of the quest to a grinding halt". GameSpot greatly praised the Game Boy Advance Version version's graphics as being "gorgeous" and the backgrounds as "quite beautiful and detailed, even if they're also static and repetitive". 1UP showed similar views, saying that while the graphics are nice, their repetitiveness weakens its impact. IGN described the fights as being "a real drag in Riviera", and that the "each fight is hedged by a number of annoying rules". Overall, 1UP said that Riviera was "lengthy, engrossing and above all unique", and GameSpy called the game "one of those unusually entertaining titles that takes time to genuinely appreciate".
The PSP remake received a lower score than the GBA version on GameRankings. 1UP considered the PSP remake as more of a port than an enhanced remake. The site thought that the graphics "are only slightly reworked", and that the art "merely looks like jumbo GBA sprites". GameSpot, also noted that the "character sprites, while impressive on the GBA, don't hold up quite so well now".