Fading Suns
A dark-ages sci-fi game set in a decaying empire where technology is distrusted¸ dominated by the Universal Church. The system is based on rolling a d20 under attribute+skill¸ where degree of success is determined by the ""blackjack"" method (i.e. your actual roll equals your success level¸ unless you fail). - A description from https://darkshire.net/jhkim/rpg/encyclopedia/ with kind permission of John H. Kim"