This game is almost an exact replica of the original. There are a few differences, though.

1. There are some question blocks in this game that are not in the original.
2. The flag pole is the elevator thing, but that is in all the 83+ Mario levels, so I don't blame you.
3. If you find a fire flower and then hit an enemy so you are regular Mario, and then grab the fire flower, you become fire Mario.

Otherwise, this is a fantastic replication.