Here is the full list of all 8 Bad Mechanic Playtest achievements.
Beat the demo without selling anything
Beat hard mode (but theres no hard mode in the playtest so you get it just for winning normally)
You are now morally obligated to wishlist the game
Complete level 1 without missing any cash
Skip 60 seconds of intermission in one run
Complete level 1
Pick up a chicken egg
Spend $300 in the shop