At the start of TaD, the GM describes a mission and gives everyone a drink. Everyone then makes a character; choose the character's Class; Hacker, Doctor, Soldier, etc. When your character tries something hard, the GM secretly chooses a number between 1 and 5; higher number means harder task. Then, you take any number of drinks. If you Class is good at the task, the GM takes the first drink for you. If you drank at least the GM's number, you succeed and the GM must take a drink; two if they chose 4 or higher. If you didn't drink enough, you fail and you must pour roughly 1 drink of your drink into the GM's drink. If your drink runs out, you crash. You fail (if trying a task), the GM describes a twist of fate against you and replaces your drink. If you suffer three crashes, the GM can remove your character (kill, capture, etc). If every character is removed, the mission fails and the game ends. If the GM's drink runs out, they replace it; if they run out again, the mission succeeds and the game ends.
Take a Drink is, as the subtitle implies, a roleplaying game combined with a drinking game. I actually haven’t playtested this with alcohol, as I don’t actually drink the stuff myself. One character can not succeed at a mission; they just don’t have enough drink. Two or three players is ideal.