Although short (the jam's only 48 hours after all), The idea shows a lot of promise. As Morgan Walkup said, I could definitely see this being really engaging with multiple party members/classes.

This system promises a lot! do not abandon your concept here and explore some more with it. It surely has it's balance flaws now, and it seems spamming the first one is the only way to go until your opponent commits to a 10+ seconds first attack, but this is super cool.