Here is a list of level 2 upgrades so far
IMPROVED ROOMS
Lair
+50% Sleep speed, +50% health regen, + happiness while sleeping
Hatchery
+50% Food generation, +100% food health, + happiness while eating
Treasury
+100% gold stack size, -20% rooms & traps cost
Library
+25% research speed for same price, researching creatures gaing a small amount of exp during research up to level 4
Training Room
+20% training speed for same price, maximum train level increased to 5
Workshop
+25% research speed for same price, 50% crafting speed
Guard Room
+50% movement speed, food and rest decay reduced by 50%, regenerates guarding creatures over time
IMPROVED TRAPS
Barricade
+50% HP, spikes return 50% damage on melee (max 10)
Spore cannon
+25% HP, +25% damage, AOE
Gas trap
+25% HP, +1 aoe range, reduce attack range by 1, +100% dot duration
Scourgelings nest
+25% HP, +20% damage, 50% damage in life steal