If you want to downpatch to the release version (1.02) of KUNAI through Steam, the developers kindly made the process very easy.

1) Find KUNAI in your Steam Library. Right-click it and select Properties.

2) Navigate to the BETAS tab and enter the pass code "speedrunningislife" to gain access to the release version (1.02).

3) Select "speedrun-d1r" in the dropdown list and KUNAI will automatically downpatch to that version in Steam.

After the download is finished, launching KUNAI through Steam will launch 1.02 and not the current release version.

If you want to update KUNAI back to the current release, navigate back to the Properties->BETAS tab and select NONE. Steam will automatically download the correct version like before.