if is the 1st version you install is probably because you dont have the pygame lib installed (I removed the dependence tag because I wanted check different versions and inever set back properly the .deb).
Anyway installing 'solarwolf' (a game with the proper installation process) should fix that.

If it is not the 1st version and other versions worked could be someething in the .flipclock.conf under /home/user. Deleting it should help.

To have the real error anyway you should try to open the X terminal and launch the clock with
paste here the result in case any ov the above idea worked out for you.
thank you for spendig time on this

@Rassilon7/steve
yes, the idea will be to save the 'mode setting' and 'alarm status' in .flipclock.conf: Like usual I just rush the .deb (still need to decide where put the am/pm and make a new graphic for the mode slide).
Buona Domenica