Unfortunately I wasn't able to figure out how the spell casting works. But the man kept telling me I missed.
Viewing post in Spelaris: Rise Of The Rune Mage jam comments
Thanks for testing my game out. To hit the rune to possibly cast a spell, it has to be in the centre of the screen and if you do it too early or too late you will miss the rune. However, the feedback is good as I thought the hitbox for the runes was big enough so definitely will change when I get the chance.