Hallecu Shaders adds wavy, distorted effects across blocks and water surfaces. That is a big part of its dreamlike style. Some players find it uncomfortable, especially during long sessions or fast movement.
Easing into it
1. Play in short bursts at first. Take breaks and look away from the screen if you feel dizzy or get a headache.
2. Move slower. Sprinting and flying across wavy terrain feels more intense than walking.
3. Lower your FOV. Turn down Field of View under Options. A narrower view can make the motion feel less overwhelming.
4. Stay away from big bodies of water. Water surfaces also get the distortion effect.
Checking the pack's own options
Many shader packs come with their own settings menu.
1. Go to Options → Video Settings → Shader Packs.
2. Select Hallecu Shaders.
3. Look for a Shader Pack Settings button.
4. If it's there, browse the options for anything related to waving or distortion. Turn those down and test the result in-game.
If the pack offers no such control, you can still switch shaders off for tasks that need precision, like detailed building. Many loaders also have a toggle key you can set under Controls, which lets you flip shaders on and off without opening menus.