Alpha 19.4 fixed these achievements! Thank you all for the support on this guide :)

I found these achievements to be broken ever since the newer Alpha versions have been released.
To unlock these 3 achievements, you'll have to roll back to an older version of the game
(Alpha 15.2)

Step 1: Go to your Steam Library and locate the game
Step 2: Right click the game and select "Properties"
Step 3: Select "Betas"
Step 4: Opt into Alpha 15.2
Step 5: Once selected, you may close this window and a download will start

Friendly Reminder: The download that has just started will not interfere with any of your save games/world, nothing will get corrupted!

Once the files have successfully updated, you are now ready to launch the game and get these achievements!

This achievement is pretty straight forward, simply, just craft an axe.

This achievement requires you to break (not sprain) your legs. To do so, simply craft some wooden blocks (I would suggest 10) stack them on top of each other and jump off. There's also the harder way and that is to find a cliff high enough to jump off.

You feel lucky? I don't, cause for this achievement you have to find a .44 Magnum (this gun takes Magnum Bullets) and kill 44 zombies. This achievement is quite tricky since it's pretty hard to find a Magnum. The easiest way to find one is to buy it from a Trader.

Please Note: If you made a world in any newer Alpha version, you cannot load the world on any older Alpha version, due to the risk of the world getting corrupt.

Congrats! You've unlocked the 3 broken achievements! Now all you have to do is simply go back to the current version of the game. Opt into "None" and wait for the game to revert back to the current version.

Hopefully this guide worked out for you! If you have any questions or want me to add/change anything in this guide, let me know :D