I'll echo the comment about grammar and punctuation. You can get by without proper syntax in forum posts, but if you are going to put in all the trouble for a decent/major game hack, you should at least make an attempt at using proper English in the hack. If English isn't your native language, I/we could rewrite your dialogue to make it at least semi-professional.
Is Hell Nebula supposed to be available after defeating the Undead Core? There's no game save after defeating the Undead Core, and since Boss.exe is still being used, I can't open the door to Hell.
That "bouncing" nonsense happens if a player moves towards the edge of the island after exiting the Last Cave.
Would it be too much to ask to move over the rocket to right a bit at the outer wall screen? With Booster 0.8, the margin of error is really small as is, and if you screw up, you won't always be able to fall back onto the rocket (and then you get that annoying "fall off the screen but won't die" problem). It's easily the most difficult ... anything in your hack. It would be one thing if players didn't have a machinegun, but since a L3 machinegun removes all of the difficulty, it really seems a bit cruel to make things that much harder for L1/L2 MG users (seeing as they also tend to be slightly weaker players to begin with).
If you are in doubt about the difficulty of anything you do, it's probably too hard if it could involve instant death or near instant death. Otherwise, it instead might be too easy.
Regarding the Sue's Workshop problem, I think Shmitz was able to put together a workaround, because he's used a Balfrog-based enemy proper in his hack, Jenka's Nightmare. Maybe Shmitz could help you out if you ask nicely.
Keep at it.