Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks some open questions after ending game

I finished nearly everything. Something is open.

1. How can I go to the magical looked door in the storeroom near the Harbor in Cyseaal? I "accidental" kill the wards with a Meteorrain but no one have a key.

2. I found the last figth very hard, so for the next turn: is it possible to kill all the townsfolk everywhere to get more XP to reach one extra Level, or will this break some quests?

3. you can put Spikes on shoes to avoid fall down on ICE. Is there a way to avoid "slow down" in the desert storm?

1) Just ask interact with it and win the RPS "game".

2) I found the last boss just way too easy and am happy that they ended up buffing them with the last patch. Almost everything that you kill gives you XP. You can finish their quests and kill them afterwards if you really want to get another level or two. During my playthrough I have reached lvl 22 without killing anybody in the towns, although I have attacked most of the opponents that would initiate a fight if you lose the Charm/Intimidate/Reason minigame after earning the Charisma XP.

3) You can cast haste spells during the battle that temporarily cancel the slow effect.

Thanks!
The last figth is boring me! the Dragon has more then 8000 HP ans my Party make max 200 per turn (all together)