I’m genuinely impressed by HeyGen’s Avatar IV. What stands out immediately is the fusion of simplicity and sophistication: from a single photo and a short script, Avatar IV creates a fully-animated, expressive video avatar — complete with lip sync, facial micro-expressions, natural head movements and even hand gestures. 
In my experience testing it, the results feel remarkably human. The model seems to interpret tone and rhythm, not just mimic them — there’s a tangible sense of timing and emotion. 
The fact that you can animate not just humans but also stylised characters, pets or even anime-style avatars extends its creative potential enormously.