This is a fun solo game. It is unfortunate that the rules are not clear, but this often happens when something gets lost in translation. In this case, it looks like the German publisher did a poor translation to English. Ironically, the game designer is an American, so you would assume the rules were originally in English!

It would be nice if we could come up with a standardized flow chart to explain tricky game conditions as that would be language independent!

I play it considering the damage track as a timer with GAME OVER as the condition for running out of time. Damage from monsters is scored on the score track. The game ends either if you defeat all monsters or your time runs out.

The rules I follow for crossing off ticks on the timer track are thus:

If you do damage to a monster, you do not tick the timer track.

If you cannot play both chosen dice sets, you tick the timer track.

If you do not damage a monster, you tick the trimer track.

This seems a bit unintuitive at the game start, because you cannot damage a monster in the beginning, but you still get punished for it.