How to Modding
There are a lot of mechanic of the game you can modify.
First, Look into game folder\Bundle, for example:
- SteamLibrary\steamapps\common\SteamWorld Quest\Bundle.
Second, the file you can mod is in the file "data01.impak".
- Create a copy or back up of the file "data01.impak" for example "data01.bkk"
- Rename the file you want to edit "data01.impak" to "data01.zip" and look for for the folder name "Definitions" (inside the data01.zip)
Third, Modify xml file you want, game codes is not difficult to understand and the files you may want to look are:
- cards.xxx.xml, to mod card mechanics
- constant.xml, to mod some of game rules, for example amount of card each heores can select, amount of card you can re-draw for each turn
- heroes.xml, to mod heroes stat / level / exp mechanics
- shops.xml, to mod items, cards you can trade or craft
Finally, replace the file you had modify into folder "Definitions" inside "data01.zip" and you rename "data01.zip" back to "data01.impak"
P.S. Don't forget that if the game update itself, you have to mod your file again.