Spellcasting can be interrupted
When casting a spell, the animation can be canceled at any time by pressing the "ready spell" key again. This was not possible in the original engine, and may be frustrating when accidentally pressing this key, the magicka cost would be spent but no spell cast. Also this could be abused to achieve faster spellcasting by canceling the attack follow animation.
Related: The same technique can be used to cancel shooting an arrow (also not possible in original engine). We may want to keep this behaviour.
(RM-2445 from redmine: created on 2015-03-11 by scrawl ., , closed on 2017-08-30 by Andrei Kortunov, relates #2835 (closed))