2919 is really cool. REALLY cool. For those that don't want to go to the trouble of putting it in, it's one of those oddly colored gems.
I imagine that 1060 (and 1080) could be used well in screenshot edits.
2480 - An odd sprite of a vertical unused gun. Well worth looking at.
2489 - I have no idea what this is supposed to be but most people will be interested in it since it has no clear relation to anything in JJ2.
2555 - Similar to 2489, except colored differently.
2580 - Is this what I think it is? A diagonal shot from an unused gun.
2581 - 2581, only angled even MORE oddly.
2582 - Another one of these, at another odd angle.
3190 - Just so everyone knows, here's the "Chuck box," even though Chuck is the other bird. In other words, this is the "(name of the other bird) box."
3095 - Yeah, it's the TNT box.
3089 - Nothing unique, but you should definitely look at this one.
3060 - Great. This post is going to be excessively large if I keep finding weird stuff.
3314 through 3321 - Look! See!
2980 - The "Super" version of that oddly colored gem. Apparently, this item is related to the Red Gem and could probably be brought into JJ2 without any trouble.
0483 - Many people fuss over "Big "B's"" so I feel it necessary to point out their number.
0673 - WOOHOO! MYSTERY SOLVED!
0674 - Those that have poor eyesight should look at this instead of 0673.
0675 - Marks the beginning of the Jazz sprites.
1373 - Marks the beginning of the Spaz sprites.
2050 - Last of the Spaz sprites, only to begin the sprites of the small songbird that Spaz eats and the small spaceship that he shoots. For those that have never stood still for more than a few seconds, they're used in idle animations for Spaz.
2073-2082 - These go together to make a strange animation.


Okay, it's getting late now and my fingers are tired. Having tried about 2000 different sprite entries (not knowing how long it took), I have found a few interesting things. I will find more tomorrow, I promise.
Oh, and I think I know the reason the Laser Shield causes crashes, but I want to look into this before I reveal it.