Grimrock

I did find out this behaviour a few days ago.

If you throw a rock at the floor it will be get picked up automatically when you step on that tile, but this isn't true if the rock is thrown and ended up in the water, even if you step on it. Is this an intended behaviour?

Ranged weapon ammo never gets auto-picked-up when it was mouse-thrown. To trigger the auto-pickup ammo needs to be attack-thrown (right-clicked).

I think I launched it from a sling, with rmb. Not entirely sure though.

I just tested it. When I throw the rock by right-clicking it or a sling, the item auto-picks up when I jump into the water and go into its tile. If I throw the rock by picking it up and left-clicking on the main screen, it's not automatically picked up when I walk across it. This confirms what Dr. Disaster wrote.

Nice. Thank you very much both of you for claryfing things up.