The idea of a metroidvania text adventure is quite a strong fit. Furthermore, the lack of visuals along with the atmospheric music do a great job of helping to build this feeling of exploring the unknown.
I do have a few small issues and things I think could be improved upon. Most evident is the movement, A,D to go left and right (ok) and U,I to go up and down......what? I'm very curious as to why you didn't make W,S the vertical movement keys as it would have made movement much more natural which would be particularly helpful when I have to backtrack or redo parts that I died to, speaking of....
The fight. The colour puzzle is alright but it carries with it some issues. Firstly, figuring it out, whilst not hard on it's own, becomes a bit of a chore when I get terrible RNG, missing and getting hit multiple times in a row. As such the fight feels quite random.
Secondly, I'm not too familiar with text games but I imagine context puzzles are important, because context can be built upon with writing flair and allows us to pick out key information and draw connections. Here, having it simply be "shoot the pink" doesn't make any sense from a contextual standpoint. I guess it's closer to blood? Perhaps more flair would help, something like "it's head was pulsating pink at the rate of a heart beat, covered in veins" would suggest that it's more vulnerable without being a complete giveaway (assuming the other colours had more description, perhaps consider texture as well which I think tells us more than colour. An alternate and possibly better approach could be to establish pink as a vulnerable colour. Perhaps you did this an I just missed it, but having something that's pink be shown as harmless and vulnerable could work if you draw attention to the pink-ness, or how about having those weak easy to shoot creatures "explode, plastering the walls with a eerie glowing pink" to establish that pink represents the blood of this planet.
My final nitpick is that nothing really comes across as me solving it when the game tells me the solution. I think "perhaps I can use bombs on the cracked surface" only to have the game say "HEY YOU CAN USE BOMBS ON THE CRACKED SURFACE!". In a text adventure where I can say "use x on y" it opens up a lot more freedom, and whilst I wouldn't quite expect that here, a little more freedom would have helped. Rather than letting me use bombs only when applicable, let me waste bombs as anytime, that way I have to actually consider when to use them.
This might be too complicated or not really fit, but perhaps if you don't want too much typing you could have certain key words or phrases (cracked wall, monster, ect) be highlighted in text. Then, when you use a bomb, you click the entity you want to use it on. I can see why this might have been too much work for the jam but it would add a lot of depth.
Rant aside, I do like the game for it's innovation in blending two compatible genres whilst building an atmosphere and it would be cool to see it improved upon.