Commander Keen was a fallback game for the smoothing side-scrolling engine that Carmack made and that iD pitched to Nintendo for porting their games onto PCs. N

Commander Keen was a fallback game for the smoothing side-scrolling engine that Carmack made and that iD pitched to Nintendo for porting their games onto PCs. Nintendo refused (surprise!), so the engine was use to make Commander Keen instead. That is, the notable thing about CK was its engine, which as innovative as it aged very quickly. There's still some nostalgic value there I guess but the target audience is probably quite limited.