I think Psion summarized it a bit too much but I can understand that.
Alternity was very good for many, many reasons.
1 - Character creation - Step one was to have a character concept. This was a description of the character you wanted to play. This did need to be some what specific. It helped to have a background idea for your character. From this description, all other choices are made. And some of them can be quite different.
Also in character creation, the six attributes ranged from 4 - 14 and you had 60 points to distribute as you wanted. It only required an 11 to get a modifier. A lot more choices here.
Personality, i.e. Charisma, determined Last Resort Points, which made this a non throw away stat unless the player wanted no ability to effect their die rolls.
2 - Die rolls - The die roll mechanic is low, as was said, and had degrees of success. They also had a control die (the d20) and a situation die (another die but d10 wasn't used) to add or subtract from the roll. This gave a bit more of a bell curve. It did mean you still have to add up modifiers but that converted into a die to either add or subtract.
Degrees of success is such a HUGE thing that I don't know if I can adequately describe how it affected things.
Further, the game rules said that unless it was an exceptional, or heroic, circumstance, most of the time, rolls aren't needed. For me, again, that was huge. Instead of having to roll to learn or fix something, the character automatically does, unless it is a hurried situation.
3 - Skill based system - The profession of a character gave a bonus with regards to buying some skills. Otherwise, it is a skill based system, which means that any character can learn anything. It did get complicated to figure the cost but not overly so.
Skills were limited to 12 total ranks. With a 14 ability score, that would mean they would only fail if their total roll was LESS THAN 26! So, they would generally get the lowest success. However, it would take a LONG time to get that many ranks, even if the GM is generous with achievement points. And again, this isn't the norm but didn't ruin "game balance" (I hat that term) if someone has above a 20, imo.
Skills had "rank benefits" that automatically happened at certain ranks. They could be bought early if desired by the PC. There were some VERY good benefits with this! For example, after 4 ranks of pistol, the character can automatically draw and fire with no penalty.
4 - Advancement - all done via achievement points, and based on profession. Some skills and ability scores are easier for some professions to improve. Yes, ability scores could go up by two each.
There were perks and flaws, some of which could be gained after starting. Flaws could be bought off as well.
5 - Perks and flaws - They existed as part of the core rules. They worked to help flesh out the character. They did give game rules of how to run them, and some of them were quite good.
I am stopping here and I haven't even begun to scratch the surface of why Alternity was good. I am not talking about how skill effected damage, how a better roll meant better damage or how the game handled scaling very well. Without a very good understanding of the basics, none of these would make any sense.
The game was its own system and is very, very good. When I played a Fantasy game based on it last year, I only modified two small things. Otherwise, I used the system as is and the players enjoyed it a lot. So did I!
One reason that I like Alternity so much is because it helped shift the focus from the generic to the specific character. So, instead of being defined by "class" and "race", the character is defined by their background. We referred to character background a LOT when making decisions about the character.
Players got a lot more control over their character's actions, imo. It was much easier to succeed, if you really needed to. This allows a shift from the die rolling to the story telling and what is appropriate for the story by the rules. I like that.
Speaking of the rules, many rules in the GMG were about the story and what the GM wanted to do. If the GM wants a detailed combat system, it is there. If the GM just wants to eye ball it to keep the story moving, that is possible as well.
If Alternity had a more developed "magic" (FX) system, I would probably still be using it. Heck, if it had gotten one revision, which probably would have added what I wanted, I would still be using it. I will still use it as my first choice for Modern or SciFi gaming. For Fantasy, though, I found that Exalted fit my style better, so that's what I am using.
I know I didn't do the system justice but this isn't an easy task to describe a system. Further, some of the things I have learned after playing Alternity for years are tough to show or explain to a person who has just started. For example, Alternity has a much better "alignment" system, which is probably where they got the d20 Modern allegiance idea. It is tough to read this, though, and understand how it all works and fits together.
A good question! Thanks!
Have a good one! Take care!
edg
former Alternity pimp
current Exalted (WW) pimp