I like it, and would recommend the game, but I'd honestly rather have a new game in the same sort of genre.
I think that it'd be possible to take elements from a variety of games like Terraria, Starbound, Noita, maybe Oxygen Not Included and do something even cooler.
Noita models at the pixel level rather than the tile level and has a physics engine.
Starbound has neat atmospheric lighting effects. I'd love to see that, maybe add in fog, godrays, glare, etc.
Oxygen Not Included lets one build devices. Terraria and Starbound let you build bases, but they can't really do anything.
If the budget permits, high-res art would be neat. Pixel art lets the brain interpolate a lot, fill in the lack of detail, but if they have the budget to do the higher-res stuff, I'd like it.
Leveraging the 3d hardware might be nice. IIRC Terraria and definitely Oxygen Not Included use it for zooming, but I don't think much else. Various distortions and other effects would be neat.
Ditto for multiple threads. Yeah, it's a cost in dev and debugging time, takes some work, but you can get maybe an order of magnitude speedup. CPU single-threaded speeds haven't improved much in about two decades.
The control is...kind of clunky. I'd love to have something with the feel of, I dunno, Super Metroid or something, one of the successful platformers.
More music, maybe effects like lighting that pulses in time with music, better dynamic transitions.