This a more classic SRPG entry, there not much innovation outside of the basic gameplay loop but there is nothing bad with that. The first map is a really good start with a fair amount of challenge, and a lot of paths to take to victory.
The second map is a bit weirder... the reinforcements just keep coming and coming, and they are no scrubs, I guess since the objective is to reach the boss and trigger an event instead of simply fighting killing the reinforcements and getting that chest is just an Extra challenge.
And then the last map has an interesting idea... but I'm not sure I like the execution, it was bit bigger than it needed to be. Getting straight to the boss takes like 8 turns, that if you're too weak to beat him need to reset or just get back and kill the side guys to get the level ups you need.
I'm really not a fan of the FE sprite splices, less so when they mix with generic portraits of the RTP since they really clash in style, and is not like they where a lot of portraits either, could as well go all out and make the generics use FE splices too.
The writing wasn't bad, but I think it may have been too much for the lenght of the game, conversations extend beyond the point various times to give context to things when it was not needed... and the mention of the tournament feel just trivial and tacked on, if I removed the idea of a tournament existing all the events would happen all the same... Cato's friend even says so "we can find him if we look for him" I know the jam has a Theme, but it was stated it was totally optional no need to force it like this into the plot.
And the 3rd chapter while interesting in concept... it really has nothing going for it, It could have been a long cutscene and achieve the same dramatic effect.
And lastly, I'm not a fan of permadeath on game with such a small cast and enemy quality this high, basically losing anyone meant reseting because otherwise it meant to keep going with missing function... not that the game is not beatable with a low party, since I lose Roselind and Axe guy in chapter 2 and still made it in chapter 4. Is more I didn't think they were dead because they appeared in chapter 3 otherwise I would have loaded the chapter 2 save.
Overall the game started strong, and the weakness started showing as it when on... I enjoyed the first 2 chapters and started to feel annoyed in the last. I hope you keep working on this or other projects to get better and build upon what you got right.