LuckyFox has begun work on a mod for Cave Story+ (from Steam or Epic game stores) which will replace the alternate story mode in Cave Story with Star Fox characters, visuals, and sounds. For those who don't know, in Cave Story+, you could play the game from the perspective of Curly Brace instead of Quote, which is largely the same as the regular mode, except that dialog sequences are a little different. You can see concept art and the work in progress version of the in-game sprite in the image above.
In the mod, Krystal replaces Curly Brace, Fox will replace Quote, the Blade weapon will be replaced with Krystal's Staff, and the Spur weapon will be replaced with a Blaster. LuckyFox is also working to remix some of the game songs to be more Star Fox like while still retaining the Cave Story style. LuckyFox sent a sample remix song of Mimiga Village.
LuckyFox is working on the dialog portraits now, but this is still pretty early in the mod's development. Right now, the modded mode is called "Krystal's Story", but in the end, it will probably be called "Krystal's Path". You can follow LuckyFox at @AizaFoxy on Twitter for news and updates on the mod.
Best of luck on this endeavor, LuckyFox!