Boulder Dash (and by that I mean the original Atari 800 version) is one of those games that'd been cloned to death. Which would have been all right with me since I love the original to bits. I've played and played and played it till I had memorised all levels and their solutions - I guess the next step would have been learning to play blindfolded :).
But the thing is, most of those clones stink. Almost none get it right; the sprite would move too slow, the rocks/diamonds would move wrong, the butterflies/square things would follow other rules, the fire button won't do what it's supposed to (halt the player and dig to the direction you turn the joystick), the levels would suck, the scrolling would be slow or nonexistent etc etc. Mind, as you noticed I only touched the core gameplay issues here. Pretty graphics and sound are totally secondary since this is a game that's defined by its brilliant gameplay (not to say that the original wasn't coded properly, in fact it's pretty awesome!)
And then there's this:
Doesn't look like much on the surface, but if we omit the fact that all the sprites move smoothly instead of jumping one block to the other, it's a damn perfect reproduction of the original. The levels have been lifted directly from there. The level goals, the timings, everything seems in place. I wasn't absolutely sure about this till I came across the first bonus level, where you're awarded with 1 life and if you pass the level you get to keep it, otherwise you die and move on.
Back then I could pass that level about 6 times out of 10, so I went ahead and tried the exact timing I was using. It worked. That sold me :). Ok, granted, the game runs at a much slower pace than the Atari 800 version so I had a better chance, but still that was pretty amazing I think!
So, big thumbs up from me, and I'm pretty sure that if Peter Liepa ever comes across it, a big smile will appear on his face :). Ah yes, here's the link. Go play it!
P.S. if you check the screenshots you'll see that they say "Nyan" - that's just the language selection I made, there are other languages too :).