Around 6 hours to complete all the levels. These are all of the unique stages that were only accessible through the E-Reader on the Gameboy Advance. These were cards that you purchased that contained unique stages not in the original game. Alot of these stages are harder than stages you would find in Super Mario Bros. 3, but also include alot of new enemies and enemies from other Mario games mixed in, as well as mechanics from Super Mario Bros. 2, like picking up vegetables and throwing, etc. I didnt realise I could exit back out to the map screen after grabbing power ups and bring them to other stages, otherwise I would have used that more, to get a good start. I used it a few times toward the end. The para beetle riding stage was one of the hardest for me, followed by Bowser's Last Stand. There is no ending, but I completed all the levels. They are all emulated. I was not going for any of the collectible coins, just beating all stages.
Deaths edited out. I am almost done with my warpless Super Mario Bros. 3 run for the original NES as well.