I love the idea of the lore you proposed. It's a very cool concept. Look up OneShot if you don't know it, it has a similar idea (I don't wanna spoil hehe) and I think you can take some inspiration from it.
I do not have any more feedback. I haven't tried hardcore mode yet either, but it's nice that you added 2 more trap types there. I'm trying to play the other submissions as well so I will try to come back to hardcore mode when I have time. I would say generally for traps you want to add a variety in terms of how the player will interact with it. For eg lava pits and spike pits are very similar mechanically: the player just has to jump over them. A trap that shoots bullets at you on the other hand can require more complex interaction depending on where the shot comes from/how fast it is. I did not see the 2 trap types you added in hardcore mode so I can't give more specific examples, but the point still holds generally speaking. I think the way you used spikes is good because in many instances it requires careful thinking when navigating them. Maybe you can build more on the wall jump mechanic and add spikes on walls that the player has to jump over.
I'm still very much a beginner, so take my opinion with a grain of salt :D. Anyway cool game!