The only thing it lacks that would make it a textbook classic RE is the character selection at the start, but everything else is a huge improvement. It has the best cutscenes, the best controls (especially the dodge mechanic, quick 180, ability to walk the stairs yourself), more dangerous enemies, the best intro, the best soundtrack, the most terrifying and memorable boss, the most best weaponry (with addition of gunpowder, enhanced ammo), more memorable characters, more logical plot with more intrigue, horrifying death scenes, gore (RE2 lacks decapitation and the character deaths are censored), better atmosphere and location variety, many alternative scenarios affecting the outcome.

It's also the most difficult compared to its predecessors due to lack of ammo/healing items, faster and more unpredictable enemies (especially the nemesis) which is the quintessence of survival horror.