From memory, I'm pretty sure most of the QTEs in that game are more than just a "press this key at this time" scenario. First off, you want to repeatedly tap rapidly (mash) the key when it's flashing.
For the finisher moves, whenever you see a circle, you have to move the cursor into it before mashing the indicated key.
The :24 mark in this video shows the mouse prompt with directional arrow telling you where to move the cursor before mashing the key for the finisher move.
I thought it was a pretty good game, shame to miss it on a misinterpretation of how QTEs are performed.