HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

If you need a completely standalone version (that doesn't require the disc (image) in the drive, including all video clips) in English, you should look for Heroes of Might and Magic Complete (GoG) (GoG.com). But not on GoG.com itself, because you'll have to pay there; instead, find it on some torrent sites. If you need a Russian version, you should look for the disc image from Buky.

If you want, download it, but in any case, I'm already downloading this Geedunk from torrents and will see what it is.