The Cosmonaut was never given a complete story. In the item description for the Makarov, it states that "The Makarov was brought to the Gungeon by a lost Cosmonaut. Some say that the brave, lost soul still wanders the Gungeon". This shows the Cosmonaut did come to the Gungeon, even if they were simply lost, as the description states, and it hints at the possibility that they failed in getting to The Gun That Can Kill the Past, and are stuck inside the Gungeon.
If the Bullet That Can Kill The Past is used on The Cosmonaut, it will send the character to the credits instead of a unique past.
The Cosmonaut plays very differently from most of the other Gungeoneers in the sense that all they have is the Makarov. It would be best to get more weapons and Passive items as quickly as possible to help with survivability. Otherwise, the Cosmonaut plays no different from any other Gungeoneer.
- The Cosmonaut does not have a bosscard, but rather uses one that appears to be a grey variation of The Cultist similar to the Gun Cultist.
- Interesting to note, the Grey Cultist is fumbling with a pistol and bullet in their bosscard, rather than the normal Dart Gun and dart.
- The Cosmonaut was discovered in the original Enter the Gungeon release, implying that they and The Ninja were likely cut or scrapped during development.
- The game's win and death screens call The Cosmonaut The Cultist.
- The Cosmonaut's map icon is The Convict's.
- NPCs refer to The Cosmonaut as "Spaceman" or "Comrade".
- In the credits, the Cosmonaut's body is a skeleton, similar to The Cultist.
- Upon opening a Chest, the Cosmonaut will salute.
- Attempting to use the Jetpack as the Cosmonaut will result in an odd sound playing and the item not properly activating.
- The Cosmonaut was probably based on a conspiracy theory called The Lost Cosmonauts or Phantom Cosmonauts. This theory holds that Soviet cosmonauts went to outer space before Yuri Gagarin and died in the process, but their existence has never been publicly acknowledged by either the Soviet or Russian space authorities. This is supported by the starting Cosmonaut gun the Makarov, which is based on the real life Russian firearm Pistolet Makarova (Makarov's Pistol), and by the Cosmonaut looking undead, as well as the Cosmonaut's nickname of "comrade".
- Due to what appears to be a skull in their helmet, there is a possibility that the Cosmonaut is based on the Vashta Nerada, a species of carnivorous beings from the British television show Doctor Who, who at one point consume the Doctor's allies and uses their skeletons and space suits as puppets.
- The Cosmonaut appears in pictures on the walls of the office section of the R&G Dept.
The Cosmonaut's painting in Exit the Gungeon