Unity of the Elements

Perhaps you have an outdated version of the game installed, which is causing these issues with completing the quests? Otherwise, I'm not sure what could be causing the problem, as there shouldn't be such obvious glitches.
Regarding the final boss, unfortunately, it has always been relatively easy to find vulnerabilities in the AI, so in the current version, he should be the most suitable opponent, at least for most players.
In any case, thank you for the positive feedback!