If it were a regular Joe console, I would say the Switch would have to best the N64 in sales to be considered a success. As it may be effectively replacing two product lines, I would imagine Nintendo would see anything short of SNES numbers to be a failure.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."
Latest Video: Top 12: Best Games on the N64 - Special Features, Episode 7







