Since your game i set in the dawn on man, you could put the element of being the first to do something. The inventor of some technology, the discoverer of a phenomenon (magic?), the first one to meet a god.
I would like being the first to discover magic, in other games they're always talking about the ancient wizards who were so powerful and unraveled the arcane secrets, or the prophets who were contacted by gods and got something taught to them.
In a paleolithic setting you could have magic based on rock painting, ritual dancing, music and fire.
that would work quite well if there were magic in the game, but there isn't, and as of now there are no plans to include it. many features in the original version were stripped out as unrealistic when the decision was made to go for realism.
likewise, gods make no appearances anywhere. your relations with them do affect things, but its all in the background. if it takes a long time to find fruit and its always rotten, odds are you've fallen out of favor with the god of plants, and should make some sacrifices. think superstitious caveman religions. the 6 gods cover the basics: earth, sky, fire, water, plants, and animals.
being the first to do something.... right now, all firsts are personal firsts. the first time you successfully make a stone knife and no longer have to run from everything you see, you feel like GOD! since everything is based on skills and research, as you progress, you add technological capabilities to your repertoire, things like making fire, making stone knives, flint weapons, clothing, cooked food, etc. so in that respect its all about firsts and new technologies and capabilities. sure you can trade for a bow and arrows, but the ability to make your own when this one wears out? much better! but all firsts are personal firsts. its not like you invent the first stone tipped spear ever or something like that.
if i implemented older hominid species, there might be a possibility to do some true firsts. but there you'd be homo habilis, limited to non-hafted technologies, and invent hafting (a skill in the game), allowing the creation of hafted tools and weapons. but such innovations were usually tens of thousands of years apart. so at most one true advancement per game would be realistic. no research tree possible. not with reserch times measured in 10,000 year increments, and a player lifespan of just 50 to 100 years.
this is the challenge of the design, keeping it realistic, yet fun. if i lost the realism requirement, everything would become so easy. i could do anything i wanted.
but from play testing, it appears the continuity of a realistic VR world has its own appeal. probably the same way that realism in flight simulators enhances the experience.
and its not an experience you get from your typical game. there is no place truly safe. unlike a level based game, such as your typical shooter or fps/rpg, you can't walk up to just outside activation range of a bad guy and see him just standing there waiting to be activated. all encounters are random. just like the real world, anything (within reason) can happen at any time. this is an actual virtual reality world, as spoken of 20-30 years ago, when game designers were just beginning to imagine the possibilities with 3D graphics and virtual world building.
i've probably spent two years just on research.
examples of questions still to be researched:
1. population density, one caveman encounter per hour, or per month?
2. is there an extra health risk from cannibalism ?
overall, i've spent about 5-6 years on the game (3 versions, one never released (v 2.0) ).
needles to say, this is way overkill for your typical shooter or FPSRPG.
but it does provide an immersion that you don't get in those types of games.