Just Die Already is a ragdoll physics game marketed as an old people mayhem sandbox title. Some of the team previously worked on Goat Simulator and a similar concept is used. The game offers a sandbox environment where the player is free to to explore to complete challenges from a bucket list or find creative ways to die. There are four senior citizens to choose from (Kamala, Lucky, Stanislav and Wally) and it is possible to switch between them when respawning. After finding a way to get kicked out of the retirement home the entire game world is available to explore. The game starts in the city center but soon several other districts are discovered such as the docks, a zen garden, the park, a sports centre and so on. Next to movement the character can jump, toggle ragdoll, interact with the environment and carry items in one or both hands to drag or use them.

The game is filled with dangers that can damage the protagonist such as electrocution through electrical devices, sharks in the water or getting run over by cars. Dying is a core concept of the game to pursue deliberately. A character can respawn at any moment and then turns up in a nearby trash container. Not all damage is immediately fatal as the characters can also lose one or more limbs and then bleed all over the place as they shuffle about. There are also many items to be discovered or unlocked to cause mayhem from guns to explosives, and vehicles such a bulldozer, a scooter, a forklift, a jet ski, a glider and so on. Due to the ragdoll physics there are many humorous elements such as taunts, a banana gun to cause people to slip or funny billboards. The game is also filled with secrets through hard to reach passages, interactions, keys that unlock gates and other creative ways to get inside locked rooms.

The main challenges can be tracked through a bucket list, with an overall one for the entire game next to specific ones for each area and some of the vehicles. Completing life goals from the bucket list is rewarded with items through three types of vending machines. Red ones dispense weapons, Yellow ones dispense utility items and blue ones dispense ticket items like special weapons and customization through hats and other types of clothing. These JDA tickets are hidden in hard to reach locations in the environment, in addition to the bucket list rewards, and they act as a currency required to buy the special items in the blue vending machine. The game supports cooperative and competitive online multiplayer.