Palladium combat rules were a bit of a mess, and it has been a long time since I played, but:
You got actions based on the level of Hand to Hand Combat training you had (None, Basic, Expert, or Martial Arts). Each combat round was divided in… 4?.. and there were actions that took half-round or full-rounds (casting spells and using a full clip from an auto.atic weapon, for example).
Full clip fire added a x10 damage modifier, which meant that basic fully automatic rifles were, on average, the deadliest weapons in the game (a laser rifle might deal 3d6 damage, a plasma missile might do 2d6x10, but that means the laser rifle on full auto would do more damage than the missile. They kept trying to add new weapon types (pulse weapons, burst weapons, micro missiles) but nothing was ever as effective and deadly as a basic weapon with full auto.
Attack rolls were opposed by Dodge or Parry rolls (depending on range and equipment), and then damage was divided into SDC and HP (Structural Damage Capacaity and Hit Points), with SDC being damage you could soak without immediate downsides and HP kinda being like you were taking serious damage now.
There was also MDC (Mega Damage Capacity) to represent tanks, Veritech Fighters,
Zentradei Battlepods, Coalition Cyborgs… anything that would shrug off bullets for ever. 1MDC was approximately 100SDC, but only 1 direction (a tank shell would obliterate a car, but a million SMG bullets wouldn’t harm a Destroid). For Robotech that worked okay… you would use SDC weapons on pilots and MDC weapons when they were in Veritechs or Destroids, but in Rifts it was a lot murkier since some PCs were MDC creatures (cyborgs, dragons, some Juicers, high level psionics) but others were only MDC in armour or power armour suits (Glitterboys, SAMAS pilots, Mages, etc).
Magic was horribly, horribly poorly balanced. It was just super weak. There were 2 types of super-human mods (Mind Over Matter, called “mama boys”, and Juicers) and the Juicers were just enormously better in every way with downside that they only lived 4-6 years, which was irrelevant for 99% of PCs and campaigns.
Skill checks were percentage based from 01 - 98% (always a chance of failure), and the list of skills was long, and your access to skills was defined by your OCC (Occupational Character Class). Generally, the more skills you got, and better, the worse you were at combat, but since the game was so focused on combat you were heavily penalized for playing anything aside from a combat OCC.
And oh gods was there ever power creep. Every source book kept coming out with newer, shinier weapons and armour and OCCs.
And a lot of very casual racism… Rifts Africa is notoriously bad, but Mexico, South America, and China source books were questionable at best…