Start of the game

[Zepondrax]

At the start of the game, three is so many doors that don't open without a key, but it seems you don't get the key and move on to more area.

Next thing I noticed after the boss fight there is an area with a ledge you can't reach by jumping yet there's a grey black there. I thought you could maybe push the block to the right to stand on then jump onto the ledge but you can't, you just move on and forget it. Little odd.

[Aldourien]

See this.[en.wikipedia.org]

[Behold The Esoteric]

Dude, you get abilities later on that will allow you and incentivise you to come back to get them later, same thing with the locked doors, you'll get keys for those.

"Little odd" says the dude that's clearly never played this type of game before.

Maybe Google what a Metroidvania is or Castlevania or Metroid and the kind of gameplay they entail before you start complaining and asking questions.

G0d d@mn the younger generation is a bunch of smooth brain goons.