Codex Gamicus

"GENETOS" is an indie vertical shooter game or "shoot 'em up" developed and published by Tatsuya Koyama with an "evolution" theme. In GENETOS, the levels represent different generations in the evolution of shooting games.

The video game was developed entirely by Tatsuya Koyama who provided the graphics, programming and music, creating GENETOS entirely himself. GENETOS is free to download from Tatsuya Koyama's personal website, downloadable in either Japanese or English from the corresponding page.[1][2]


The gameplay of GENETOS is focused around the evolution of "shmups" or shoot 'em ups throughout history. The game starts off with simple graphics reminiscent of Space Invaders being a "Gallery Shooter" or "Fixed Shooter" having limited graphics, music, movement and sound effects.[3]

File:Genetos Stage 2 Gameplay.png

An example of gameplay in stage 1 of GENETOS, which shows similarity to Space Invaders

Each level or generation gradually goes further in the history of shoot 'em up games moving into a late eighties world with free-movement restricted to half the screen, a "more standard" level improving the layout and graphics of the game and giving the player more fire power and giving the player bombs which can be used with the X button on the keyboard. The 4th level in the game features simple 3D graphics and shifts to a "Bullet Hell" game featuring much higher amounts of bullets and larger amounts of enemies.[4]

The 5th level of GENETOS or the "Final Generation" changes largely in tone following a story more so than the levels before. the player travels through various stages of evolution such as birth, variation and extinction loosely following the theory of natural selection and Darwin's theory of evolution.[5]

Each level ends with a boss or a "mutant", triggered by gathering enough items allowing the item bar to be 4/5 full or collecting 800 of a 1000 total items. Filling the item bar will allow the player to "evolve" into the next generation of shooting games, improving graphics, fire power and special attacks of the players ship.

Scoring in GENETOS is mainly done by picking up point items which are blue rather than regular items being green, in the 3rd level the player can stop shooting to allow powerups and items around to drift towards the ship and further in the game this becomes faster allowing the player to collect items easier.

Collecting green DNA powerups in GENETOS allows the player to gain the special attacks and bonuses, these are found in various places in the games by defeating enemies. The way the player plays through GENETOS affects the special weapons they get, playing in certain ways, dying or staying alive, staying in certain areas of the screen or defeating a boss with a weak ship can unlock these bonus weapons, helping the player throughout the game.

The difficulty of GENETOS varies depending on the era of game it is portraying its self upon, getting more difficult with each generation ending as a "bullet hell" type of game.[6][7]


The soundtrack of GENETOS consists of 14 tracks used as background music in-game. All music was composed and arranged by Tatsuya Koyama. An additional three tracks were included with the full release of genetos being "Origin", "Answer" and "Rebirth" to be used in the final level and the newly added credits. Soundtrack can be accessed by entering the "Sound test" section in the game menu.

File:Genetos Stage 5 Gameplay.png

An example of gameplay in stage 5 of GENETOS

All songs written and composed by Tatsuya Koyama. 

No. Title Length
1. "The Planet GENETOS"    
2. "Preperation"    
3. "Little Invader"    
4. "Big Invader"    
5. "Lonely Galaxy"    
6. "Lonely Universe"    
7. "Blue Sky"    
8. "Dark Cloud"    
9. "Dawn of a New Era"    
10. "Price of Prosperity"    
11. "Origin"    
12. "Answer"    
13. "Rebirth"    
14. "Game Over"    

Release history[]

The first version of GENETOS, 0.50 was released on 20 December 2007. Version 0.60 was released on 10 August 2008 having most of the basic features. It featured the first 4 levels in the game, ending after the 4th level unfinished and lacking credits. Version 1.0 of GENETOS being the completed version was released on 24 December 2009 being the first full release of GENETOS and the current version; many features were added such as "history" system which allows the player to complete achievements or collect hidden green DNA powerups in game to obtain special weapons. The 5th level was also added, adding the conclusion to the game finishing with new credits. Various other aspects were released with the first full version of the game such as a new title screen, other menus, more music and graphics in the game. The game is currently in its completed state according to Tatsuya Koyama.[8]


GENETOS has been generally received well, often getting praise for its unique concept and portrayal of the history of shoot 'em up games. The game has received slight criticism or has been noted for its difficulty citing the amount of lives and bombs saying "the game on its default level of difficulty is generous with extra ships." but also that "the stages are appropriately difficult to reflect the trend of complexity in shooters, the game on its default level of difficulty is generous with extra ships.".[9][10]


  1. GENETOS homepage gives these descriptions. Tatsuya Koyama. Retrieved on 5 June 2010
  2. Softonic review, information and download page. Softonic. Retrieved on 5 June 2010
  3. GENETOS homepage describes its similarity. Tatsuya Koyama. Retrieved on 5 June 2010
  4. GENETOS homepage describes the stages in the games. Tatsuya Koyama. Retrieved on 5 June 2010
  5. The "final generation" is split up into different stages titled: birth, variation, selection, prosperity and extinction; similar to the stages of natural selection and the theory of evolution
  6. Information of the game from the Indiegames blog. Indiegames "timw" user. Retrieved on 5 June 2010
  7. A general overview of the game and a review. playthisthing!. Retrieved on 5 June 2010
  8. There is a small release history on the homepage. Tatsuya Koyama. Retrieved on 5 June 2010
  9. Auntie Pixelante review. Retrieved on 5 June 2010
  10. A short review for GENETOS. Retrieved on 5 June 2010

External links[]