The Tequila Starrise System uses a modified version of the Alternity (1999) system. "TSS" will be used to abbreviate that going forwards

TSS is a d20 skill-based system system. The players roll a d20 (control die) dice plus or minus a modifier dice (situation die) and aim to roll UNDER a specific score.

Degree of Success

Almost all stat scores (Broad skills, Skills, Action Check etc) in the game have three values Ordinary, Good and Amazing success scores, abbreviated as O / G / A. The Ordinary value equals the base score of that stat. Dividing the ordinary by two (rounded down) gives you the "Good Success" and dividing this by two (rounded down) gives you the amazing amazing score. For example an Ordinary score of 14 will mean that the good success score will be 14/2 = 7 and the Amazing success score will be 7/2 (rounded down) = 3. Any roll ABOVE the Ordinary success score is automatically a failure. A roll of a 20 on the control dice is an automatic Critical Failure.