Bayo 1 has some bullshit design choices like insta death QTE that come out of nowhere, Megaton/Gigaton attacks being almost impossible to fill at max (this is very frustrating) and generally more cheap difficulty from enemies. There's also the lack of variety in the game locations and related to this is the lack of color in general. The attacks feel less impactful and powerful than in Bayo 2 and the story is presented in a very confusing way.
All of this is fixed and/or vastly improved in Bayo 2. Plus, we get online co-op (and offline on Switch), far more interesting weapons, Umbran Climax (some people dislike this for making the game easier, I on the other hand think is incredibly satisfactory and gives magic a more defined purpouse) and a bunch more stuff.
Don't get me wrong: Bayo 1 is still a great game and it even has some edges over Bayo 2 like better bosses, (slightly) better soundtrack, more interesting non-battle mechanics/levels... But when I tried to replay Bayo 1 after having played hundreds of hours on Bayo 2... I just couldn't. It felt so downgraded and clunky to play...
