The game is a top-down Bullet Hell shooter that borrows heavily in terms of gameplay style from CAVE's games. Unique to this game is its take on the Smart Bomb: Firing at enemies and destructible bullets and cancelling bullets with your bomb raises a Charge gauge, which can be expended to fire a bomb, the strength of which is dependent on your Charge level when you fire it. Firing a bomb clears out bullets in its path, and also generates star items as it plows through enemies, alongside the stars that are normally dropped when destroying enemies.
An Updated Re-release for arcades, Aka to Blue Type-R, was released for the exA-Arcadia platform. A 3-stage location test was held in some arcades in Japan, as well as game-related events in France and the United States.
There are currently no known plans to bring the game to console or PC.
Aka to Blue contains examples of:
- Bullet Hell: Like almost any modern shoot-em-up, the game will fill with bullets very quickly.
- Charged Attack: Collect type. Shooting enemies and cancelling bullets will raise your Charge level, which determines how powerful your Smart Bomb will be when you deploy it.
- Colourful Theme Naming: All of the named characters are named after colors: Aka (Japanese for "red"), Blue, Murasaki ("purple"), Kuro ("black"), Ao ("blue"), and Dr. Brown.
- Men Are Strong, Women Are Pretty: Aka is the male half of the protagonist pair and is a muscly Boisterous Bruiser, while Blue is the female half and is comparatively soft-spoken and sports a fairly average body type.
- Nintendo Hard: As an arcade-caliber scrolling shooter, it pulls no punches in its attacks. While the smartphone version does give you the option of enabling automatic bombing, and bombs can be rapidly re-obtained if you play your cards right, it's still easy to get overwhelmed by the bullet curtains especially on a relatively small smartphone screen. Type-R is even more difficult; whereas your lives replenish back to 3 at the start of each stage in the smartphone version, this version does not, as is standard of arcade shmups.
- Protagonist Title: Aka and Blue are the two Player Characters.
- Red Oni, Blue Oni: Aka is the hot-headed Boisterous Bruiser, while Blue is the more calm, collected type.
- Smart Bomb: You can fire a bomb of varying strength that's based on your Charge level. A Level 1 bomb simply clears bullets around you, while higher level bombs are large projectiles that go through bullets and enemies, though it's important to note that unlike in most other shmups, bombs don't remove all bullets from the screen. An optional toggle lets you fire a Level 1 bomb automatically if you get hit with at least a Charge level of 1 or more, though it will use your entire Charge gauge. Additionally, the angle of Blue's bomb can be adjusted within a cone in front of her.