Players choose one of many characters with different weapons and starting bonuses, and control them on an endless stage with auto-generated, repeating layouts. The player's weapon automatically attacks, and the goal is to survive as long as possible against waves of monsters that continuously deal damage as they come into contact with the player. Defeating monsters and exploring levels allow players to collect experience gems, which are used to level up, "floor chickens,", which restore the player's health, and other useful items. Each level up gives the player a choice of three or four weapons and passive power-ups; once a player has collected six weapons and six powerups and fully upgraded all of them, any subsequent levels they reach offer only gold coins or floor chickens. Another way to upgrade weapons and increase their power is to open chests that are dropped by particularly strong monsters and can contain one, three, or five random items. Most weapons have a "ultimate" form that can be unlocked by opening chests after they have been fully upgraded and certain other conditions have been met.
Vampire Survivor sessions have a soft time limit of 15 or 30 minutes, depending on the stage chosen. At the time limit, the stage will be empty of enemies and the extremely powerful final enemy named Death will appear. An additional Grim Reaper will spawn every successive minute after that to ensure the ultimate death of the player. A session that reaches or exceeds the period time limit is considered successfully completed, and gold coins are awarded. Between sessions, the accumulated gold can be used to unlock new characters and continuously power up. Additionally, by completing challenges, players can also unlock new levels, weapons, and characters.