Working my way through it right now and I have some praise and critique for this hack so far.
First thing's first y'all nailed the Brutal Mario aesthetic perfectly. Love the graphical choices as well as references to franchises I know fuck all about. I like how the first stage is a full on throwback, the second is fully Bomberman themed (which as far as I know was never referenced in the original Brutal Mario), and idk what the third stage is based on but it reminds me a lot of the three castles in World 8 mimicking the three final bosses of Trials of Mana in the original game. The third level in particular has some very impressive ASM that's really fun to play with.
My biggest critique so far is that I did
not enjoy the second stage. It's not irredeemably bad by any means and I think the bomb gimmick was mostly implemented well enough, but it was extremely difficult and not in a good way. The level very much felt like a slog to get through with each section being very long with nowhere near enough powerups to match the difficulty. I tried to avoid using savestates but I gave up after dying over a dozen times in the second section because it became very repetitive and I just wanted to see the rest of the game. I found the third section challenging at points even with savestates, especially during the P switch/spring section near the end where split second decisions are life and death which seems kind of unfair toward the end of an already very long stage. I also really struggled with the boss even with savestates because the further along you get things move at such a breakneck pace that it's hard to get a grip on what's going on.
I also really didn't like how the custom tank and fire wheel thing (?) sprites couldn't at minimum be spin-jumped on or killed with the bombs, but idk if that has to do with their functionality in whatever game they were pulled from. Feel free to take these critiques with a grain of salt because other people may enjoy the challenge and I could just suck at video games but I really didn't enjoy it. If you take away anything from this, please just add one or two more powerup blocks per section.
My only other spare critique is that I feel like using some of carol's ports (especially in stage 1) feels a bit too on the nose but that could just be me.
Also I'm stuck on one part but I don't wanna spoil it for those who haven't played so if you wanna go in blind don't click on this!

Past this part you need the key again but unless I'm stupid there doesn't appear to be another one after this and I have no fucking idea how to get the key beyond this point. I tried kicking it up before freezing time but I can't stand on it as it ascends.
Those are my thoughts so far. Despite my distaste for stage two I can really feel the love put into this, I'm sure you guys will score very highly!
EDIT: Found a potentially massive problem.

I tried kicking up the key at an angle so I could jump off it and then have it land on the upper platform but I missed the jump and it flew up there. I couldn't go far enough offscreen to make it spawn back in it's normal position so this is a borderline softlock with the only way to fix this being killing yourself and starting over. I might not be the only one who tries this when playing blind so it's something to consider looking into maybe, idk what to do to get around this tho.