On my way to Fuschia but posting some thoughts.
Game is basically straight up Fire Red with Digimon swapped in for Pokemon. Thats fine, would love to see it take on a life of it's own some day because I love Digimon.
I will say there are some pacing problems.
First off, the difficulty increase isnt noticeable until Brock where it completely broke down. I am not sure Im remembering correctly, but Gotsumon and Kudamon were his digimon I think? Gotsumon was easy to one shot with water moves from lower level, but no idea if moves are even available to beat Kudamon that early. Im just now as I write this seeing that hes water rock, which I never would have guessed. Just a weird typing for him in the first place. Im sure theres probably a grass move available somewhere, but I dont think I ended up with a grass type mon 4 badges in.
Beyond Brock however the difficulty curve evened out and at least up until where I am now (bridges south of Lavender on the way to Fuchsia) game has been very easy.
Some of the level scaling feels off - like Punimon doesnt digivolve to a rookie level mon until 20? Thats pretty painful as you try to play the game just due to base stat totals. Ill say even more painful when you arent actively looking at the full pokedex in this post because punimon I would have assumed would digivolve into tsunomon then gabumon - I did not realize until writing this up that baby and in training are treated as the same level here.
Move power scaling also seemed a bit problematic. For instance, you can get Dragon Rage fairly early on and just spam that for OHKOs all day because nobody has over 40 health - and if they do, its still only two hits which is way better than most other moves at that point. Similarly, when I unlocked Greymon with nova Blast enemies just became a joke again for a while. So at certain points you feel overtuned, and early on when all everyone knows is a bubble move and some stat moves the game feels incredibly slow and lacking in strategy. Im not sure if you followed fire red move levels or kind of just went with your own pacing, its been a long time since I played fire red and cant remember if that is an issue. I KNOW that new games avoid this issue and you basically start with type specific moves and get very wide move coverage early on. Might not be a problem with this hack and just a problem with Fire red pacing relative to newer games.
Overall, having fun, but also a lot to be desired. Id give it a 5/10 (where a 5 represents basically same quality as vanilla game, anything below 5 being changes that detract from game, and anything above 5 adding to the game).
Have some small nitpicks about some of the sizing of sprites, some of the pacing issues I mentioned, etc, but improvements to HMs and including custom moves (even if they might need some fine tuning) evens you out to a quality pretty much on par with the released game.