There are some enemies that have some sort of a crystal shield and they are unbeatable. I tried every type of granade but ther is nothing to do, is it normal or am I missing something?

I've been playing this for hours trying to work out what I was missing. Eventually caved and watched a walk through and found out that the key I need for the first red door is behind a wall I missed. I can't get through it though because I accidentally threw my last grenade a while back. You only seem to be able to buy firecrackers which don't open the door... Is that it? Am I just stuck now and supposed to start again or is there another way of getting grenades for this?...

I did all the achievements in the game, but the Scrooge achievement doesn't appear on my Steam profile, what can I do??

I seem to have hit an issue which is stopping all progress for me (only at the second map page) I can't seem to jump high enough to reach platforms, it must only be a couple of pixels short. They clearly look like they shouls be reachable but after 10 mins of attempting stationary jumps/running jumps, I'm completely stuck. All the passages out of the area are key locked or tech blocked and the route back out of the area is inaccessable due to the same jump issue. I can't progress forwards or backtrack...

I have found myself permanently stuck. Im in a room with a save point that I am attached to. If I go to the right there is a series of times platforms you obviously need double jump for, which is something I haven't gotten yet. On the left there is a room where I am on the wrong side of a key door. The door is closed and I never found that key yet. And if I die I'm stuck at a save point in the middle, no way out. Any way to reset where I revive? Or do I just have to start a new game?...