-I don't see a way for me to sell items (possibly intentional)
Advice for possible future feature:
Allow adventurers to sell items, however each shopkeeper only has X amount of gold for buying items and shopkeepers only buy items which match their trade. For example a blacksmith would buy weapons, yet would not buy potions. This worked great for Neverwinter Nights created by Bioware.
-The adventurer never seems to level up despite having a level displayed.
Advice for possible future feature:
Allow adventurers to increase levels from killing enemies/monsters, however each type of creature can only be killed X number of times before experience ends. This would stop someone from sitting around killing rats to reach a high level. One step further would be adding quests/puzzles which also provide experience.