OneLife_v231
If you want to update, first run the normal client and let it make the update, then follow the install instructions.
In order to install, you already need to have the normal version of the game.
Then download the binary "OneLifeApp_H_windows" and place it inside your One Hour One Life folder.
For steam users this folder is at C:\Program Files (86x)\Steam\steamapps\common\One Hour One Life
Then execute the downloaded binary
If you run into problems, please search in your ohol folder for cache.fcz and delete all that contain that name.
Then log in once with the normal client, before starting the mod.