Error 500 on load

There's many reasons that this could happen, below are the ones that I know about; you can figure out which your error is related to by checking the log file located in storage/logs.

No column named "ID"

This is due to a schema change that I wasn't aware of, a more production ready fix is being made but for now it's possible to modify your tables to add an id column to the respective tables:

ALTER TABLE `fight_players` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY;
ALTER TABLE `stats` DROP PRIMARY KEY;
ALTER TABLE `stats` ADD `ID` INT NOT NULL AUTO_INCREMENT PRIMARY KEY;