Those are good suggestions! It's exactly that I'm looking for ^^
Yesterday I tried adding a big city level as an intro level, but I didn't think it was as exciting as a more focused single goal stealth mission. I'm considering a prison escape as a more exciting intro stealth mission, if that doesn't turn out to be too difficult for new players as a first mission.
Right now I'm working on a floor trap which the player can sabotage. With a mission goal to let a guard have an accident with its own trap.
Unlocking characters could be an interesting progression and reward mechanic. I hadn't considered that yet. Could I already lock 1 or 2 characters from the current 4 characters with the option to unlock, or would that be mean at this stage because they've been unlocked since the first version?
Requiring 100% gold might frustrate some players, so I might use that as a bonus objective. Along with other bonus objectives, such as "no knockouts" and "no alerts". Maybe combining bonus objectives with unlocking characters as you've suggested.
How would a forest level work with stealing gold? Or do you mean a forest level similar to the first two missions in the current demo?
I will look into that candle bug. Did the guard re-light the candle when that happened or was the candle like that from the start?
Thank you for these suggestions! They are very helpful to me ^^