From a review:
The d00Lite system is a percentile based system. There are two types of die rolls called in this game: Percentile/d100 based rolls (where success is based on rolling under the target percentage) or standard “D” rolls (rolling a number of d10’s and adding the results.) Task resolution is percentile based; the D rolls are usually for stuff like damage, healing, generating stats etc.
An interesting take that makes this system stand out from other percentile systems I’ve played: 00 is counted as Zero, and is the best roll to make. 0-5 always succeed, 95-99 always fails. Also different is the Critical Success/Failure mechanic: while the extreme ends are automatic success/failures, a Critical is determined whenever doubles are rolled.