Let's see:
550 points for stats is now deemed the default.
Flat 50 DPs is now the default allocation. For those using stat-derived DPs, fractional DPs are available for stats under 51.
Different races but that's not really a tweak. Humans get Skill Flexibility as an alternate to Profession Adaptability. Humans now also get TEN stat points to distribute between the 8 stats.
New professions, but again not really a tweak. however the idea of professions have a choice of professional abilities is something that will be retro-ported into HARP Fantasy.
Genetic Adaptation talents replace racial Blood Talents.
Different Cultures, but again not really a tweak.
New skill categories (Scientific, Technical, Vehicular), new skills for psionics, another RR skill, etc.
Mandatory Subskills for Air Pilot,
Animal Handling, Beastmastery, Driving, Foraging/Survival,
Machine Operation, Marine Pilot, Riding, Signaling, and Space
Pilot skills, rather than learning the same skill as separate specialisations.
A number of talents have been recosted or revised to correct imbalances.
More adventuring rules to cover more situations. Fighting on Water and Watery Hazard rules altered.
More Combat Actions, stun RRs changed, more crit tables.
Psionics.
Best wishes,
Nicholas