Tune1: Nicely done; I noticed later on it somewhat deviates from the original slightly, but I definitely like it! It does sound like the main melody needs to be a bit louder relative to the rest though. This is pretty much my favorite tune from the DOS games, so I might be a bit overly-picky on this one.
Tune2: This one, it might be just me, but a lot of the notes sound off-key in the first half. In the second half, I can't really make out much of the main melody.
Tune3: Definitely a lot of freedom taken on this one too, and once again, it works out very nicely. I actually don't like this track originally (in either DOS or Amiga versions), but your one is very good!
Almost sounds like it has a country music spin to it, in a way.
Tune4: The first bit is a bit too silent; needs a bit more backing I reckon? There again, it is based off the Amiga version, which itself is also like that.
Tune5: This one sounds like a mix of the two versions, pretty interesting! In the part that'd be the first part in the Amiga version, it sounds like you cut off the longer notes too soon and use silence where the note should be extended more. Also, I think you cut the intro a bit shorter than it should be? It kind of sounds strange cutting off after just one repetition of it instead of two. That being said, this track is overall very well done!
Tune6: This one sounds fairly familiar to the original on DOS, nicely done.