E.g. SPACE or ENTER (like in ADOM II). The game then needs to analyze the environment and offer all possible commands in a reasonable presentation. And allow selection by pressing one key. It should include actions like "open door to the west".

The idea here is to help new players by explaining one command for item usage ('u') and one for environment interaction (e.g. SPACE or ENTER). Combined with one movement command for exploration ('-') you suddenly need to learn very little.