Chikyu Boueigun: its lineage, descendants, and standing in Japan
01What this origin is
A likely, but not developer-confirmed, root of this taste: THE 地球防衛軍 (Chikyu Boueigun), an action-shooting game developed by Sandlot and released as SIMPLE2000 Series Vol. 31, published in Japan by D3 Publisher for the PlayStation 2 on June 26, 2003 (and in Europe on February 27, 2004, published by Agetec under the title Monster Attack). Rather than one giant hero facing down a single kaiju, it drops the player into repeated short skirmishes as one soldier among many, ordinary-scale defenders holding a city against a relentless, overwhelming alien invasion, mission after mission. It became the first entry in what grew into the long-running Earth Defense Force series, whose later installments carried that name internationally, and it set a template that lineage has repeated ever since: a small, mortal defender thrown again and again at a threat too large for any one of them to end alone. The Last Salvage Squad's CogrinaUnits carry that same premise, city-scale swarms of alien war machines met one short encounter at a time, into their own distinct core: a unit that falls is simply replaced by the next one, armed with whatever weapon its predecessor managed to salvage. We found no statement from Sunfish Kumano naming Chikyu Boueigun or the Earth Defense Force series as an influence; this lineage is a comparison independent reviewers, including the Japanese blog banshu-doukoukai.com, have drawn, not one either side has confirmed.
02Sources
03Buried gems that carry this root
The Last Salvage Squad Buried gem
A single-player 2.5D FPS in which you pilot CogrinaUnits, 12-meter-tall autonomous humanoid units built to keep fighting after a gargantuan alien warship all but wiped out human civilization in a single stroke, developed by the Japanese solo creator Sunfish Kumano and published by Waku Waku Games, a one-person publishing company whose sole representative is Ryuji Oyanagi. Missions play out as short, hard-edged skirmishes against alien war machines styled after the multi-legged combatants of classic Japanese sci-fi and tokusatsu, and per Steam's own feature list, every one of them opens with the same choice: use the terrain to pick the enemy apart from range, or close the distance and finish it up close. Equipment stays scarce by design. When your unit is defeated, the next one is sent out immediately, and it inherits whatever weapon the fallen unit managed to drop, a 'hand-me-down' salvage loop that re-arms you out of your own losses rather than a shop or a levelling system. Between fights, the game settles into lighter conversation scenes with fellow units, plus, per Steam's own listing, 'a shiba inu'; one of its eight Steam achievements, 'A Bone to Pick,' appears to nod to that same dog. This is the full version of Sunfish Kumano's earlier prototype Hand-Me-Down, which established that same weapon-salvage core, and this release carries it forward with new pickups, among them a katana and a rocket launcher, and built-out presentation. Released June 17, 2026 per Steam's own listing in both its Japanese and English pages; some Japanese outlets, including 4Gamer and GAME Watch, reported June 18, a one-day gap we read as most likely a Pacific-time listing quirk rather than a correction, and note here rather than silently pick a side. It sits at Very Positive, 98 percent per Steam's own store page (399 of 405 reviews positive per Steam's review API), single-player only with full controller support, a paid title at ¥1,500, not free, fully launched and not in Early Access, with no AI-generated assets and, by Steam's own content descriptors, nothing sexual (ids: none, notes: none). It supports Japanese, English, Simplified Chinese, and Traditional Chinese, and about 217 of its 405 reviews, roughly 53.6 percent, are already in English, a clear majority; outlets including Kotaku, Noisy Pixel, and Game Critix have already reviewed it, so calling this a gem the West has not found yet would not be honest. What is true is that its total review count, 405, is still a small, early number next to any Western hit, so this reads less as a game the West has missed and more as one it has only just started properly meeting.