Slang is an imperative/event-driven object-oriented programming language.
It is packed with the best bits taken from all the languages I know of, either appreciated or not (I do look at you JS).
For example, C has pretty good (not to say brilliant) language syntax design: just try to count all major C-like languages on your fingers ;). Slang, which implements similar syntax, takes it to a whole another level, superpowered by its features.
It probably has its own bad sides, though — yet to figure out (and hopefully, eliminate).
But performance will ever be and remain a consideration, least to say.