How are video games from today different from the first video games

Early video games had to work with more restrictions, such as less powerful computers. This meant that games had to be incredibly simple (compared to modern standards).
One prime example of this is the game "Space Invaders" in which the enemies gradually speed up, this was originally accidental because the computer the game was being run on, could not process the positions of all enemies fast enough so the game slowed down, and as more were destroyed, it took less time for the program to work everything out so the game sped up to its original speed.

As more and more technical limitations were overcome, games got steadily more impressive, with better graphics, better music and larger worlds.

the removal of limitations also allowed new genres to be explored, as graphics improved games like DOOM appeared, first person shooters.
As storage space increased, the size of games got bigger, open world games began to appear as well as fully 3d rendered games.