Starting Funds

Easy

150% of monthly funds income
Base global panic starts at 0
Most alien activity only raises panic by 1 if left unchecked
Aliens use the Easy/Normal AI package, and aren't as numerous.
XCOM soldiers have +1 bonus HP, starting with 6 instead of 5
Soldiers cost $10
X-Com HQ starts 35 units of power.
X-Com HQ starts with an Officer Training School.
Sectoids have their health reduced by 1 compared to Normal
Thin Man aliens' damage is reduced by 2, and their HP is reduced by 1 compared to Normal\
Aliens use special abilities and throw grenades extremely infrequenly

100% of monthly funds income
Base global panic starts at 0
Most minor alien activity raises panic by 1 in left unchecked with some events doing up to 3
Soldiers have no bonus hitpoints
Soldiers cost $10
X-Com HQ has 35 units of starting power.
X-Com HQ starts with an Officer Training School.

100% of monthly funds income
Base global panic starts at 8 (1 per location)
Unchecked alien activity causes at least 1 panic, but will often cause 2 or 3
There are more aliens per mission
Aliens receive bonuses: Chryssalids and Zombies recieve a +2 damage bonus, Muton berserkers receive a +1 damage bonus, all aliens that use ranged weapons receive a +10 Aim bonus, Mutons, Heavy Floaters, Drones, and Outsiders receive a +2 HP bonus, Sectoid Commanders and Cyberdiscs receive a +4 HP bonus, Sectoid Commanders and Ethereals receive a +25 Will bonus.
Alien AI is unshackled
Soldiers have -1 HP
Soldiers cost $15
X-Com HQ has 30 units of starting power
X-Com HQ has no Office Training School at the start; a soldier must reach Sergeant to unlock the OTS base facility

100% of monthly funds income
Base global panic starts at 16 (2 per location)
If unchecked alien activity causes at least 2 panic, but will often cause even more
There are even more aliens per mission
Aliens receive bonuses: Many aliens do 2 to 4 bonus damage, all aliens using ranged weapons have +10 Aim except the Outsider and Muton Elite who receive +20 Aim, all aliens have +10 Critical Chance, Outsiders can move 5 more tiles per turn than in Easy, Normal, or Classic, Sectoid Commanders, Ethereals, and the Uber Ethereal receive bonus Will, with the first two getting +35 and the latter getting +10, many aliens receive +10 bonus Defense, and most aliens receive 1 to 5 bonus HP
Alien AI is unshackled
Soldiers have -2 hitpoints
Soldiers cost $15
X-Com HQ has 30 units of starting power.
No free Office Training School; a soldier must reach Sergeant to unlock the OTS base facility
Aliens use special abilities frequently, and are 40 times more likely to throw grenades compared to Easy and Normal