I'm a unity begginer and I'm working on a 2d game for the gam and the sprites are ok in the edit tab but really dim in the game window and the internet dpesn't have an explanation. Asking for a proffesional advice or someone who knows how to fix it.

Okay, so first, I would check if you have a directional light source and point it towards your scene. If you do and there's still issues, then do this...

• Create a new material, with shader Sprites > Diffuse.
• Select all the objects you want to react to lighting, go to their Sprite Renderer and change the material to the one you just created.
• Create a point/spot light at Z=-1 and you should see the light.

This is mainly for doing small space lighting (i.e. dark room with candle)