Here is the full list of all 50 Command & Conquer: Red Alert 3 achievements worth 1,000 gamerscore.
You completed every lesson in the tutorial in spite of all the bickering from the instructors
You won battles on all original maps vs. skirmish opponents (medium-or-greater difficulty)
You won on 2-player maps vs. all 9 skirmish opponents (medium-or-greater difficulty)
You won a battle in less than 5 minutes vs. a skirmish opponent (medium-or-greater difficulty)
You won on a 4-player map vs. a team of 3 skirmish opponents (medium-or-greater difficulty)
You defeated a brutal-difficulty skirmish opponent on a 2-player map
You completed 27 different online co-op campaign missions
You completed all three campaigns on medium or hard difficulty level
You completed all three campaigns on hard difficulty level
You fought your way to the heart of the Soviet Union and brought her scheming leaders to justice
You accomplished each and every bonus objective in the Allies campaign
You discovered the Soviets' traitorous plot in Havana and put an end to it
You forced the Empire of the Rising Sun's surrender by demolishing her key military infrastructure
You thwarted President Ackerman's insane plan to annihilate the Soviet Union
You sent the Empire of the Rising Sun's infamous floating fortress to the bottom of the sea
You countered the Empire of the Rising Sun's vicious attack by banding together with the Soviets
You drove the Soviets from Western Europe by breaching their fortified position in Heidelberg
You sank the careless Soviet armada rampaging off the coast of Cannes
You repelled the Soviet Union's savage advance on the Allies' foothold in the United Kingdom
You completed 18 different online co-op campaign missions
Your final triumph over the Allies and the Soviets ensured they will never change their destiny
You accomplished each and every bonus objective in the Empire of the Rising Sun campaign
You struck at the very heart of the Soviet Union, shattering her defenses and the evil time machine
You deflected your hated foes' desperate and dishonorable two-pronged attack on Japanese soil
You decimated one of the Allies' bastions of greed, making the Emperor's message clear
You resisted the Allies' disgraceful attempt to decomission Japan's prized floating fortress
You drew in and destroyed the Allies' treacherous naval forces attempting to besiege Pearl Harbor
You assembled General Tatsu's ultimate weapon and set it on a path of destruction across the Union
You erected a glorious statue of Emperor Yoshiro to bring shame and awe unto the Soviet people
You mounted a full-scale surprise attack on the barbarous Soviet Union on her sad little holiday
You completed 9 different online co-op campaign missions
You showed the Allies the flaws in their ideology and became the Soviet Union's greatest hero
You accomplished each and every bonus objective in the Soviet campaign
You did what needed to be done for the greater glory of the Soviet Union
You finally vanquished that arrogant fool who the Empire of the Rising Sun revered as a god
You took care of the Allies' secret Von Esling Airbase, and silenced a traitor to the Union
You prevented the Allies from completing their secret weapons research and took it for yourself
You assisted the willful General Krukov in eliminating the Allies' military stronghold in Geneva
You routed the Empire of the Rising Sun from Soviet soil and regained the port of Vladivostok
You wrenched the launch facility at Krasna-45 from the clutches of the Empire of the Rising Sun
You halted the Empire of the Rising Sun's cowardly and audacious ambush on the Soviet Union
You cut down 15 enemy units with sword attacks in a ranked online match or skirmish
You destroyed 30 enemy units with an ultimate weapon attack in a ranked online match or skirmish
You dismantled 4 enemy vehicles using the same Terror Drone in a ranked online match or skirmish
You captured 6 structures in a ranked online match or skirmish (medium-or-greater difficulty)
You converted 5 enemy units with a single Spy bribe in a ranked online match or skirmish
You killed 25 enemy targets in 1 minute with a Commando in a ranked online match or skirmish
You armed 10 Multigunner IFVs with different weapons in a ranked online match or skirmish
You crushed 20 enemy units in a ranked online match or skirmish (medium-or-greater difficulty)
You leeched 7 different enemy weapons using Hammer Tanks in a ranked online match or skirmish