That is, assuming you can actually get the game to work. The primary gimmick of the game is that the main menu itself is riddled with strange and disturbing glitches preventing you from accessing the game. You must use the main menu to fix them and find various passwords to access the save files; the process of doing so becomes a series of puzzles. And all throughout is a dark, unnerving atmosphere as you try to figure out who you are and what you are doing here.
This game contains examples of:
- The Ending Changes Everything: For most of the game, the narrative is incredibly vague. All that is known is that you are someone traveling in a strange Womb Level with corridors and disturbing visions. The ending reveals that Calendula is the name of the protagonist, who is a baby going through the process of birth.
- Environmental Narrative Game: An odd example in that only about half the game is this. The In-Universe game of Calendula is a first-person walking sim where you only have the option to walk forward, and pressing any other button does nothing. The first-person segments are short and only require you to walk forward for about a minute. The main gameplay is actually in the main menu itself, which is riddled with Ominous Visual Glitches that must be fixed so you can find passwords to access the files of the game.
- Foreshadowing: One of the passwords needed to progress is NPTM, but the game screws with your keyboard so you have to type in BORN instead. As it turns out, you play as a baby who is trying to be born.
- Interface Screw: Half of the game is spent in the menus, screwed up in many ways. The other half is walking through changing short corridors dominated with the colors red, white, and black.
- Meaningful Name: Calendula is a type of marigold. Marigolds are the birth flower for October, and the baby protagonist receives this name upon being born.
- No Antagonist: Unusually for a horror game, the antagonist is simply a series of non-sentient glitches that are messing with the game menu and preventing you from playing the game. The story itself is also rather vague, but despite the scary apparitions that appear, none of them actively hurt the player, and ultimately the conflict is a baby trying to be born.
- No Fourth Wall: The entire gimmick is that the main menu itself is the primary game, as you must navigate it to fix glitches and find passwords so that you can play the actual, In-Universe game.
- Ominous Visual Glitch: The game has this visual effect as its core gameplay mechanic. It essentially consists of a series of creepy and bizarre glitches that you have to fix by fiddling around with the game's menu settings.
- Rewarding Inactivity: One of the achievements, “Sorry”, requires the player to not solve a puzzle for fifteen to thirty minutes.
- Womb Level: The first-person segments of the game take place in a strange place with womb-like walls. Considering the ending, it is likely that this literally is, or represents, the womb that the baby Calendula leaves.
