Wet is an action game that combines shooting and swordplay with acrobatics and gore. The main character, Rubi, carries twin pistols and a sword (she can also carry dual shotguns, submachine guns, or crossbows), and can fire while jumping, sliding on her knees, seducing goons, and running on walls. During these acrobatic actions, the game enters slow motion, and she will automatically aim at a second enemy, allowing the player to shoot at two enemies at once. She can also combine her attacks, such as wall running off a person or performing a sword uppercut while sliding. Racking up kills and collecting multiplier icons gains multipliers, which increase score and the rate at which Rubi regenerates health. Rubi can also regain health by finding bottles of whiskey.
In some sections of the game, Rubi's face will get covered in blood and she will go into a murderous, berserker-like rage. These sections are presented in noir style, with bold red, black and white visuals. Rubi's attacks become faster and stronger to fight against large numbers of enemies during these sections, and killing chains of enemies extends her psychotic fury. There are also motorway sections that feature shooting integrated with quick time events.
At the end of each stage of play, the player will be graded on three different factors: Completion Time, Acrobatics, and Average Multiplier. Based on performance in these areas, Style Points will be given, allowing the purchase of upgrades to both Rubi and her weapons. Different upgrades include additional health blocks for Rubi, as well as increased firing rate and damage for the pistols, shotguns, submachine guns, and crossbows.