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