Here is the full list of all 55 Rusty's Retirement achievements. It takes around 120-150 hours to unlock all of the achievements on Windows.
Harvest 250,000 crops (across all farms)
Earn 10 MILLION spare parts across all farms
Place down ten pigs on one farm
Water 1 MILLION crops (across all farms)
Build on every available tile
Place down ten cows on one farm
Produce 1 MILLION biofuel across all farms
Build 666 crop tiles on a single farm
Unlock all berries
Spin the Cog a thousand times
Unlock all crops
Max upgrade a Fertilizer Bot
Collect 1,000 animal waste
Max upgrade a Waste Bot
Place 10 Bulb Hives on a single farm
Max upgrade a Feeder Bot
Build 10 Biofuel Converters on a single farm
Play the game for 48 hour (across all farms)
Grow a Giant Cucumber
Place 100 decorations on a single farm
Place 25 decorations on a single farm
Unlock the Desert Oasis farm
Unlock the Blossom Forest farm
Earn 1 MILLION spare parts across all farms
Unlock the Sandy Desert farm
Play the game for 24 hour (across all farms)
Produce 100,000 biofuel across all farms
Unlock the Flower Swamp farm
Max upgrade a Berry Bot
Unlock 25 crops
Earn 250,000 spare parts across all farms
Max upgrade a Water Bot
Max upgrade a Harvest Bot
Deploy one of each robot on a single farm
Max upgrade a Biofuel Bot
Grow a Giant Pumpkin
Build Pinion's House
Build Splunk's House
Produce 25,000 biofuel across all farms
Build Slate's Barn
Build Sonnet's Shop
Earn 50,000 spare parts across all farms
Grow a Giant Tomato
Place at least one decoration
Build Forbic's House
Produce 5,000 biofuel across all farms
Build Echo's Workshop
Earn 15,000 spare parts across all farms
Unlock 10 crops
Move a building at least once
Produce 1,000 biofuel across all farms
Build Haiku's House
Play the game for 1 hour
Unlock a new crop
Spin the cog once