itch.io

There's no need to apologize, this is the very reason to do game jams. This is the best place to test your ideas and get the feedback from the player base!
You are correct in thinking that dying on the first obstacle created caution and also you learn that each item had its own obstacle, Cheese > Cheese grator, Meat > Tender Hammer, Hob > Heat, Pot > Boiling water, So you could learn when to jump.
I do think adding a hazard sign or a "!" pop up above their head would warn them about the danger ahead is much needed and I disagree with it taking away from the game, the object would still be invisible  and they still need to find a way to avoid that object. There would still be many deaths but it wouldn't take them by surprise.

"Perhaps I could give him a sort of aura, increasing in size with each death, which would have the same effect as the splash but follow the player and allow him to identify the nearest obstacle to reveal the danger? What do you think?"
I think this is pretty cool but how I would personally implement this would be like this:

- Instead if the aura increasing with each death, have pickups/ power-ups/ collectibles on the map. The player can then choose when he wants to use that ability to reveal a hidden hazard. The player wont have many power ups, so they would have to choose wisely when he wants to use them or take his own chances/ risks.

Also, if you take a look at my first game, it was awful. I feel like my game for this jam is 100 times better because after my first jam I highly focused on "Game feel", I wanted to make the controls feel good. In my first game, my jump felt very floaty, the player got stuck on walls and so on. I would personally try to fix these aspects. The jump mechanic was the only reason why I didn't finish your game, I didn't mind the rage aspect of learning as you progressed. For me personally, focusing on Game Feel and controls made me 10 x better. It doesn't matter what game you make, it needs to feel good to play.