Updated some mechanics and fixed a few bugs.

Some bug fixes made.
- Tutorial getting stuck on D4 explanation has been fixed.
- Added some default movement for the loose arms after boss was killed so that they will start moving off the screen.
- Fixed D4 sometimes having the explosion radius indicator stuck after it was initiated and enemy blasters healed it back to life.

Added mechanics.
- Player will get scores when hitting enemies as well as when destroying them making the score display more enjoyable to see.