I know nothing of their system. Anyone care to enlighten me?
Basically, you have a d20 roll to attack (roll above a 5 on a d20 with all modifiers and you hit..you might just hit their armor and deal damage to it, but you still hit).
Opponent can usually make a defense roll of some sort (dodge or parry) to try to avoid the hit; again a d20 roll.
It also has about 8 or 9 different saving throws.
The skill system, however, is a percentage system.
The magic and psionics system are similar in function (they each use a "spell points" system), but are different enough to give you a headache if you think about them too hard.
Each Palladium game has a number (and by "a number," I mean "in the dozens at least") of OCCs (Occupational Character Classes), RCCs (Racial Character Classes) and/or PCCs (Psychic Character Classes), with different amounts of XP needed to level up.
Now, this doesn't work too bad when you're playing something like Palladium Fantasy (which is actually one of my favorite games to play). Most of the characters are fairly balanced power-wise, and characters don't have a butt-ton of attacks per round, and you don't have to deal with the dreaded Mega-Damage Capacity (one MDC = 100 SDC or hit point); also, if an opponent is wearing anything MDC (even a loin cloth), you always take damage off of that MDC first (oh..and SDC weapons can possibly scratch the paint of an MDC structure, but that's about it..even if an SDC weapon can do 30,000,000 points of damage, it's still an SDC weapon and MDC laughs at it).
Where the system really breaks down, IMHO, is in games with more powerful/faster PCs (Rifts in particular) and a vast disparity between OCC/PCC/RCC power levels. When suddenly a 1st level character has 4-6 attacks per round and can auto-dodge every attack thrown at him while another character is in a suit of power armor with several hundred MDC and can fire a gun that can can deal a couple of hundred MDC and a third character is a demigod and a fourth character ('cause you know, there's always this player) is playing a vegabond that starts out with jack crap for equipment (no MDC weapons or armor), no abilities and hardly any skills..there's an issue. (The solution, of course, is to only allow similar-powered classes, but that's not necessarily RAW).
And I haven't even gotten into rune weapons yet....
The whole ruleset is very 80s and has seen VERY little in the say of evolution since it's original inception. As a result, compared to say D&D 4e or Savage Worlds or the Storytelling System, it's EXTREMELY clunky. Best yet, Siembieda (one of the game's creators) thinks it's the BEST SYSTEM EVAR and doesn't need to do any sort of evolving or major overhauling.
And then there are the Palladium system's vampires, which I hate with the passion of eleventy-bajillion burning suns. They could literally get hit, point blank, with an attack that could destroy an entire universe and laugh it off since they (literally) only take damage from certain attacks, but they pee their pants when you come at them with a Super Soaker or child's toy watergun, since "running water" (which includes rain and being fired from a water gun..no..I'm not kidding) will have them peeing in their pants.
All that said, some of my favorite game world concepts come from Palladium. It's a matter of "great game world, bad game mechanics."