At the moment I'm rebuilding Don Pedro's caves for Krissz's site, and this made me think of this thread again - it's high time to continue!
I - I like this cave! Few non-random objects and still different ideas to explore in different parts of the cave:
First, Rockford needs to find a way to get upwards without getting stuck, collecting as many diamonds as possible on the way. The idea was not new at that time - Dr. Watson's BD4, cave I was similar.
Next, when Rockford has made his way upwards, there's a magic wall with a boulder/diamond mixture above it. Here, Rockford faces a completely new challenge: converting the boulders but trying to pick the diamonds out without converting those! That's a wonderfful, innovative new idea for that time!
Having made it to the left half, we see a BD2-P like finish.
Overall, I think this is a very good cave divided in three parts with different tasks to solve, and with the common theme of big boulder-diamond mixtures. The only downside I can see is the slow speed on the BD1 engine due to the many active elements. Of course, this is not at all Don Pedro's fault! So yes, why not - 5/5!
J - That's the other end of the innovation scale... fireflies guarding diamonds and... um... diamonds guarded by fireflies. 2/5.
K - Strange but interesting!

If Rockford quickly moves doen, he can see the first Rolling Fly Formation in his career! (Or better, rolling ghost formation ;D) So after the first DFF in BD6-B, now Don Pedro also was the first to discover a RFF! And there's a mean little troll again - one might think that the titanium wall next to the start is the exit, but it isn't! So if the player thinks that he has all the time in the world to easily collect the diamonds while the fireflies get crushed by the amoeba anyway, then an unpleasant surprise awaits him in form of 200 amoeba-rocks falling down and buring the real exit! I guess that the huge timer of 180 was made intentionally to give the player an additional false feeling of safety. So I think this troll is very much thought of and also the RFF is a clear visual plus IMO. A clear downside is the gameplay which is not interesting at all (once Rockford knows he must hurry, there are no obstacles hindering him to do so). Still 4/5 for nice troll plus RFF!
L - nice design! Basically, we have BD1-I with fireflies, which is an interesting addition IMO! The amoebas that get pre-crushed add a nice explosive effect to the start, and in fact, we see the amoeba randomness at its clearest here: there's a tiny chance that one of the amoebas might grow twice before the firefly reaches it and survive the explosion! In this lucky case, the player gets a completely different cave where the amoeba can give him hundreds of bonus diamonds! Though the cave is based on BD1-I, these new additions and innovations make me rate this cave very high too - 4.5/5! I was thinking about another full score, but the fireflies can also become annoying if they build a vortex (2 fireflies circling in the same 2x2 space) at the wrong place.
Int 3 - Not interesting but playable - 2/5.
M - what a WTF cave!!

Inside the first few seconds after the cave is loaded, the player sees a never-seen-before butterfly stack moving below the inbox, hears a magic wall which this time does not convert the amoeba (meaning that for the first time, both sounds can be heard simultaneousely!) and then Rockford hatches and sees the butterflies moving toward him and the amoeba, possibly crushing the latter and turning into diamonds which then partly convert into boulders (not all convert because a part of the magic wall might get destroyed). What a show without Rockford doing anything special!

It's very funny to see how Don Pedro discovered more and more strange fly moving habits by just putting some flies somewhere! This is probably another occasion where he "innocently" just wanted to have butterflies, made a line of them and then was stunned himself about what they did!

Possibly Don Pedro was also wondering why the amoeba did not convert by the magic wall this time. (Today we know the reason - the BD1 engine's magic wall bug was such that all amoebas BELOW a magic wall counted as trapped as soon as the wall was activated, but here, the amoeba being ABOVE the magic wall, there's no such effect!)
One tiny question remains - what the hack is Rockford supposed to do after this overstimulation?! Getting 75 diamonds from the butterflies is not so easy if the diamonds tend to get converted into boulders! I guess Don Pedro's solution was to deflect the butterflies quickly, so that the amoeba survives and converts into boulders which then partly convert into diamonds! A completely new and fantastic idea IMO!
Of course, such a mind-blowing cave will not only have fans. I remember that when I played it for the first time, I got completely confused and thought that all this was an abuse of Boulder Dash

Still, alone the fact that there is so much to write about this cave makes me think it deserves at least 4/5!
N - Dealing with butterflies in narrow spaces seems to be the topic here. But the random pushing-boulders element seems a bit unfair when failure could mean that the butterflies will follow and crush Rockford.
The strange firefly-diamond construction might indeed be an interesting playground - the firefly might chase Rockford without a gap in-between, but still Rockford can escape because the cavescanning order favors him. However, one single diamond is quite a little reward for taking such a risk IMO, and overall the cave doesn't leave a good impression on me - just 2/5.
O - yeah, the game had to get finished somehow?! Though the idea of breaking through the "firewall" by creating a BD2-K-like snake might have its plusses and the unconvertable-boulder-troll might be somewhat funny, the cave just looks like a wasteland, lovelessly created just because the game needs 20 caves... 1/5.
P - more diamond-guarding fireflies, more wall-blasting and one more firefly surrounded by dirt. On the other hand, there is some strategy involved - the first explosion is quite not so easy to do and then, Rockford has to blast the bottom-left wall before the bottom-right wall because otherwise he would run out of fireflies. However, this idea has already been seen in Dr. Watsons BD4-J (with nicer design IMO), and also the many fireflies can be quite annoying in the bottom-right corner, so I don't like this cave enough to rate it above avergae - 2/5.
Int4 - A magic-wall-stops-amoeba- int again, without any new aspects compared with BD3-int1. 2/5.
Overall BD7 gets from me a score of
56.5% from me, and also my subjective feeling tells me that I like this game best so far - it includes quite some innovative and/or nicely designed caves!