A simple Anki add-on that lets you choose which review button the spacebar selects. Should work on all versions.
How to Open the Add-on Files Open Anki Click Tools → Add-ons Select Anki Spacebar Binder Click View Files
This opens the add-on folder on your computer.
Configuration
Open the .py file (init.py) in a text editor and change this line:
return 3
You’re changing the number.
Button values:
1 = Again
2 = Hard
3 = Good
4 = Easy
Save the file and restart Anki for the change to take effect.
Better Instructions & Source Code:
https://github.com/ryleighnewman/Anki-Spacebar-Binder