I Lose Something is an online trading card game for guys that are single. This game's main selling point are the feature to collect, customize and dress up cute girls. Unlike traditional TCG or CCG, this game mainly revolves around powering up and utilize each character's ability to win the battle.

This game can be played by up to 4 players per table/board. Each player will place their main character card at the center of the board and their corresponding ability card that the player wants to use for rest of the game. The players will take the turn to attack their opponents or defend himself. Each player may play any number of cards per turn until it surpasses their character's stats. However, if the player decided to use a character-specific special ability, they must end their turn after use. A player wins if all other player's hit point fall below zero.

The winning player will get rewarded with in-game currency or other resources. These resources can be used to increase their character's stats, unlock abilities or buying cosmetic. Losing player will get ¼ of the reward. Other than the character's appearance, the player can also change their character's voices. The character's intimacy will also increase if the player interacts with them and doing things that the character likes. Higher intimacy will increase the character's combat performance and unlock certain features.

If a character's intimacy is high enough, the player can unlock their character's "personal story mode". Completing a character's story will reveal their secret and will reward new abilities. However, all the character's secret will reveal that they may look like cute girls but they are actually guys. I Lose Something gives the term "You just activated my trap card" an entirely new meaning.