Borderlands was just re-released with an updated version. They improved little bits of the game from the UI, drop rates, and new 4k textures. To me, the UI updates were the biggest changes. A lot of the UI updates took inspiration from Borderlands 2 and The Pre-Sequel. Subtle textures and glow effects were added to the health and shield bars and the inventory was turned from a simple text list to a visual list.
The largest gripe I have with the first Borderlands is the navigation through the menus. The game works great on console or with a controller. But on PC you're often using your arrow keys to scroll through a list that jumps back to the top when you mouse over something on accident. The Enter and Escape keys are frequently used to confirm a selection or back out of a menu. They did improve purchasing ammo by allowing you to press the space bar to buy all the ammo of the type selected. This was a nice improvement to keep users from going through 10 "are you sure" confirmations so they can fight that next boss.