In the second area of the game, there's a puzzle with 3 regenerating fire stones that you have to kill at the same time with the ice spell.
The problem is, the game's tutorials are a bit lacking and they don't explain to you anywhere exactly how to do this. It says you can "lock-on" but locking on with your normal lock-on button doesn't work with the charged version of the ice spell.
You have to MANUALLY aim at targets after building up a full charge, and it will just stick a "lock-on" cursor over each target, then you can press the "shoot" button to start the barrages.
- Equip the Ice spell.
- Build up a full charge.
- Use the MANUAL AIM button (NOT your normal lock-on button) and hover over each of the 3 fire stones (releasing the aim button won't lose the targets).
- Press the SHOOT button before the charge depletes (you can be standing anywhere, it doesn't matter).
- Barrier goes down, ez. continue your adventure and have fun.