Marguerite is first encountered in the "Mia" videotape (gameplay released earlier as the "Lantern" demo, indicative by Marguerite's lantern). As Mia, the player would have to evade Marguerite until getting captured by her in the crawlspace. She would roam the Old House to find her, and getting captured by her before the crawlspace event results in a game over.
While playing as Ethan, while on the second floor of the Main House outside the Recreation Room, the player can look outside and see Marguerite walk from Zoe's trailer to the path that leads to the Old House.
Marguerite later appears when the player obtains the Stone Statuette in the Old House and attempts to leave the Living Room. She will shout at the player, shutting the door in their face and covering it in spiders which prevents access unless the bugs are killed. After this encounter, she actively roams the Old House, and during this phase she will attack by sending swarms of bugs at the player if she spots them. If enough damage is done to her, an event will play where she knocks Ethan down and leaves, resulting in her no longer being present in the house.
The first boss battle with her occurs when the player has acquired the Crow Key and walks up the stairs to the locked door that leads to the Alter. An event will play where Marguerite throws Ethan down the stairs and onto the wooden floor which subsequently gives way, making the player fall into a hole. The fight consists simply of her standing at the top of the hole summoning her insects to attack, knocking the player back down if they try to climb out. After enough damage is done to her, she will collapse and fall into the hole wherein she is enveloped in a pool of bugs and slime which will continuously damage the player if they do not proceed to climb out of the hole.
The final boss fight occurs with Marguerite when they enter the Greenhouse. The fight is initiated when the player walks up the stairs to the 2nd floor, where she will burst through the window and attempt to grab the player. If caught, the player must attack her to make her let go and retreat back through the window. If the player avoids her, she will retreat anyway. During this fight, Marguerite can crawl on the walls and attempt to grab the player from various hiding spots. She will flee and hide after being injured by Ethan, before returning to surprise or hunt him down. After landing enough hits at her, she would stand up and expose her weak spot - the insect hive at her stomach. While hiding, Marguerite can position herself on several walls in the Greenhouse and create new hives which spawn some of her insects. Damaging her while she is depositing the hive can interrupt and prevent the creation of the hive. Otherwise, Ethan can destroy the hives manually. Upon defeat, she leaves behind her Lantern which is required to progress further in the Old House.