Very good, considering the GBs short memory capacity.
The Bad: Nothing much considering technical limitations
Full Review: Pokemon Red managed to perform admirably considering the VERY low memory of the GB compared to today's console. In fact, it's remarkable it fitted in at all! It's probably a good thing it did though. Moving it up a generation would put more pressure on Nintendo to hit us with everything at the beginning, which would make all Pokemon RPG games pretty much identical. For a start it is great fun let's face it, with no ending (HOORAY!!) and plenty to do, though predictably this slows down after the League, but you still have legendary birds and Mewtwo to be got. There are also a few sidequests dotted in here and there to provide a break from gym battles. These can also be quite rewarding. Many precursors to today's games can still be found here, such as TMs and HMs, and these have developed into an integral feature today. A solid foundation for the series.