"Though the main reason why it's so short is to prevent to attack through obstacles that are behind a block"
you could make sure there's no collision with any obstacle objects before it can interact with other things. Just some ideas. I love metroidvanias so I have enjoyed most things so far. I'll give it another try later today. Thanks a lot for the prompt reply btw!
Oh, one more thing, and I personally know this can be a pretty annoying thing to tackle, though I have solved it already for my games:
Implement custom controls. This will allow everyone to play your game however they find fit. Trust me when i say this, I know this is easier said than done, but you'll be glad you implemented this once it's done(hopefully).