I really should start thinking about a game name..
Here the development updates:

So after letting my girlfriend play I figured the blocking guys are creating no fun at this state (level1) for the player. I will put the shielding goblins in a later level in combination with some other goblins.

I made these chargers instead.

Also there is now cave decoration and healing potions right after the first harder encounter as a mini reward – you deserve it