The game is controlled by the arrow keys and the space bar. You move around a good sized world and examine things, collect items, unlock doors, etc. Inquisitive Dave is fairly easy, but it has enough humor and odd twists to make it also very entertaining and worth wasting some time on.
I won't give away any spoilers because much of the fun of the game is discovering things yourself. It is pretty easy to get Dave killed, but fortunately there are very frequent automatic game saves so you don't need to start over.