As you can see in the featured video of the jungle in Virmire, the first remastered Mass Effect will have a new user interface similar to Mass Effect 2 and Mass Effect 3. Moreover, the game contains new lighting effects and resources. The camera also appears to be closer to the character (so there is hope that there will be an adjustment of the angle of view). The official Mass Effect Legendary Edition page has more visual interactive comparisons of the original games with the re-release. In addition to the above video on Vermire, there is also a second video and two screenshots showing the changes in the quality of lighting and models. By the way, Shepard himself will look much better in the re-release (the developers cited comparisons of both female and male characters):

Mass Effect Legendary Edition will receive improved aiming and rebalanced weapons. In addition to 4K and HDR support and improved visual effects (models, textures, shaders, lighting, depth of field, etc. – most of all, in the first part), games will have better sound quality, better squad control, and “Mako,” improved hideouts and combat system in general, as well as a general character editor for the entire trilogy. The collection will receive improved support for controllers and 21: 9 screens on the PC, plus add compatibility with DirectX 11 and simplify navigation through the user interface.

The re-releases will differ in several other features: an almost complete set of add-ons (minus one ), the lack of a multiplayer mode, and even changed camera angles. Mass Effect Legendary Edition will be released on May 14th on PC (Steam and Origin), PS4, and Xbox One. Along with the release date of the collection, Electronic Arts has revealed its system requirements.