Yes, there's a hidden command. If you hold left shift and then press 1,2 or 3 while at the menu it should clear that slot.

Well that's just the bomb-diggity fantastic sauce. Thanks.

And for those who want to back up the save file now that they got 100%.... where would it be?

@TenDot11 Don't know about the steam-versions, since I got the standalone ones. But those didn't create save-"files", instead they relied on registry-entries. You should find them under
HKEY_CURRENT_USER\Software\Matthew Brown\Hexcells
Just export it with regedit and re-import it when you want to restore your old save. This is for the windows-version obviously, didn't try it on linux/mac.

@Matthew + @availableusername
Excellent information, thank you very much for that :)
For those who have filled the three slots to 100% it makes it easy to reset and keep track of your progress when you replay. Just picked up both titles for next to nothing on weekly sale; how happy am I?

Originally posted by Matthew Brown:

Yes, there's a hidden command. If you hold left shift and then press 1,2 or 3 while at the menu it should clear that slot.

Hi dear dev, can you add Steam Cloud support to Hexcells & Hexcells Plus, now there is only Steam Cloud support for Hexcells Infinite. It will only takes you a couple of minutes to set it up without any changes in the code, you just need to specify the save files location and enter byte quota in Steamworks.

Oh great, I have tried some program that uses that key combination and now my progress is erased :C

Linux location: ~/.config/unity3d/Matthew Brown/Hexcells