Reception
Infinite Space met with "generally favorable" reviews, earning a score of 75 points out of 100 from aggregate website Metacritic based on 46 critic reviews. While critical reception of the game was generally positive, it saw a more mixed reaction from players in both Japan and the West.
Reception to the narrative was generally positive, with praise going to its writing and scope. Japanese gaming magazine Famitsu called the narrative enjoyably complex, with one reviewer noting its setting as "overwhelming". Kat Bailey of 1Up.com noted homages to 1970s Japanese science fiction, while Edge Magazine praised the narrative as "neatly grafted" onto the gameplay systems. Eurogamer's Dan Pearson described the storyline as traditional while praising Yuri's characterization. Matthew Kato of Game Informer called the characters cliche and the story "ordinary", while GamesRadar enjoyed the balance of serious drama and humor. GameSpot's Nathan Meunier found the story predictable, though the characters grew on him. GameTrailers enjoyed the narrative and praised the localization, saying it "carefully balances between violent, humorous, and thought-provoking themes". IGN's Daemon Hatfield highlighted the characters' growth as the main reason to play through more difficult sections. Matthew Castle, writing for Nintendo Gamer, lauded the scale of characters and narrative, praising Yuri as one of the best recent RPG protagonists. Anthony Capone of PALGN cited the narrative as one of the game's positives, and Pocket Gamer's Will Wilson lauded the character interactions and script quality. RPGamer's Mike Moehnke enjoyed the character development, particularly Yuri's growth during the story.
Where mentioned, the graphics saw mixed responses. Kato positively noted the battle sequence graphics. GameTrailers gave praise to the anime stills used for cutscenes, but found the 3D ship models unattractive and faulted the sound design for its poor quality. Hatfield faulted the interface design as unintuitive and frustrating to manage, while Capone faulted both the menu design and audio quality while praising the anime designs. Wilson noted the 3D graphics and sound design as positives that helped create the right atmosphere. Moehnke faulted the lack of animation in battles, and lauded the soundtrack as enjoyable even after extended play.
The gameplay saw general praise for its customization and battle system; a common complaint across regions was high difficulty and a lack of direction. Famitsu praised the customization options and depths of its mechanics. Bailey, while generally positive, noted many obscure mechanics and the need to grind for cash to strengthen ships. Edge praised the customization options, but noted a lack of direction and problems navigating the interface; these sentiments were echoed by Pearson, who also praised the depth of battle mechanics. Kato's main point of praise was the customization systems, as he found the battles less engaging overall. GamesRadar praised the battles, but found several of the associated systems overly complex. Meunier positively noted the blend of combat and customization, but found the melee elements unenjoyable. GameTrailers disliked the ground-based battles, but praised the ship combat and depth of customization options given to players. Hatfield disliked the gameplay during the first few hours due to a lack of flexibility and generally negative about several mechanical choices, while by contrast Castle lauded its systems despite these unintuitive elements. Capone faulted the navigation as too complex, and felt that the prolonged periods between save points undermined enjoyment. Wilson was fairly mixed about the battle system due to recurring frustrations with its combat mechanics, feeling new elements were unlocked too slowly. Moehnke was overall positive despite noting the weak melee options and need for grinding.
Sales
During the first week following its release in Japan, Infinite Space sold 38,000 units and was the highest selling game in Japan during that period. Sales tracking company Media Create predicted that the game would have a 92% sell-through rate, indicating that it could continue to perform well on the market. By the end of 2009, it was among the top-selling two hundred titles, selling just over 71,400 units. Its early sales success was attributed to its broad appeal in themes, and the fact that it was an "orthodox" DS title of a type becoming rare in the modern market. It ended up selling around 200,000 units worldwide. Later speaking about its low overall sales in Japan, Kono cited the limited manufacture of cartridges due to costs as a factor. Inaba half-jokingly blamed Sega for under-producing the game, resulting in the limited stock quickly selling out worldwide, but more seriously attributed its lack of sales to the bulky scenario's niche appeal.