Is it possible that an incremental work may get selected by a top conference?
It's possible, in the sense that there's a non-zero chance of acceptance. A couple of factors strongly contribute to this chance: How well can you explain the significance of the problem? How big is the novelty delta, for example, are there some entirely new concepts? How big is the runtime improvement? How rigorous is the evaluation?

In essence, you need to write a very strong paper, which is naturally easier for some contributions  than for others.