Boring stuff only, but if you really care then I've listed the exact changes below.

General changes

Enemies

Lawnmower enemy movement speed increased 155 units / second -> 200 units / second

Lawnmower enemy base health value reduced 16 -> 13

All energy type enemy projectiles' damage reduced 30 -> 25

Energy Charger attack speed increased 1.85s -> 1.5s

Sprinkler Drone attack cooldown increased 0.875s -> 1s

Fire object lifespan reduced 5s -> 3.5s

Fire object contact damage increased 10 -> 15

Items

Steel Bar item armor increase 0.05 -> 0.075

Muscle Strength damage increase 0.25 -> 0.30

Glass Cannon armor decrease 0.05 -> 0.075

Battery Acid movement speed decrease 0.1 -> 0.05

Heavy Bullets damage increase 1.35 -> 1, gravity increase 1.1 -> 1.15

Lucky Guess has been renamed to Golden Card

Running Boot movement speed increase 0.15 -> 0.20

Strange Mushroom temporary damage increase 2 -> 1.75

Black Mesa Silly Straw™ healing cooldown multiplier 0.75 -> 0.85

Bug fixes

Fixed a glitch where the XP bar would not reset and grant a level up upon filling

Fixed a glitch where the Items Unlocked statistic could reach a number higher than intended due to garbage programming

Fixed a glitch where you could not select the Classic character class in certain conditions