The rough animation and slower humor of the first season is in sharp contrast to the caustic satire of politics and the American lifestyle the writers would adopt for later seasons of the Simpsons. The show also relies heavily on the antics of the "bad-boy" behavior of Bart, evidenced by the prank phone calls and generally sub-par intellect of Bart that would be phased out by the third season, moving more to the socially relevant scripts.
In December 1989, America got it's first glimpse at the Simpsons in it's half hour format, with "Simpsons Roasting on an Open Fire", in which we see an early critique through the Simpson writers of the prototypical American family. Being the first produced half hour episode of the historic franchise, the Simpsons' wily dog Santa's Little Helper is absent in "Bart the Genious", which showcases the underachieving intellect of Bart that would be symbollic of the show in it's earlier years.
The show in it's first season borrows much of the personalities from it's time as crude filler material on The Tracey Ullman Show, taking another season to evolve to what the show would become for the next 6 years. Also, in the 13 episodes, the writers were very eclectic in the selection of characters as the center of each episode.
The season should be an eye opener to people as to how shows evolve over the course of years. The Simpsons in it's incipient stages on DVD is a must have for any fan.