Here is the full list of all 55 Rusty's Retirement achievements.
Spin the cog once
Spin the Cog a thousand times
Unlock a new crop
Unlock 10 crops
Unlock 25 crops
Unlock all crops
Unlock all berries
Grow a Giant Pumpkin
Grow a Giant Tomato
Grow a Giant Cucumber
Build Haiku's House
Build Sonnet's Shop
Build Pinion's House
Build Forbic's House
Build Echo's Workshop
Build Slate's Barn
Build Splunk's House
Play the game for 1 hour
Play the game for 24 hour (across all farms)
Play the game for 48 hour (across all farms)
Place 10 Bulb Hives on a single farm
Move a building at least once
Earn 15,000 spare parts across all farms
Earn 50,000 spare parts across all farms
Earn 250,000 spare parts across all farms
Earn 1 MILLION spare parts across all farms
Earn 10 MILLION spare parts across all farms
Produce 1,000 biofuel across all farms
Produce 5,000 biofuel across all farms
Produce 25,000 biofuel across all farms
Produce 100,000 biofuel across all farms
Produce 1 MILLION biofuel across all farms
Place at least one decoration
Place 25 decorations on a single farm
Place 100 decorations on a single farm
Deploy one of each robot on a single farm
Max upgrade a Water Bot
Max upgrade a Harvest Bot
Max upgrade a Biofuel Bot
Max upgrade a Feeder Bot
Max upgrade a Waste Bot
Max upgrade a Fertilizer Bot
Max upgrade a Berry Bot
Place down ten cows on one farm
Place down ten pigs on one farm
Collect 1,000 animal waste
Build 666 crop tiles on a single farm
Build 10 Biofuel Converters on a single farm
Build on every available tile
Unlock the Flower Swamp farm
Unlock the Sandy Desert farm
Unlock the Blossom Forest farm
Unlock the Desert Oasis farm
Water 1 MILLION crops (across all farms)
Harvest 250,000 crops (across all farms)