Becoming a 'proper' game

Pretty big chunk of work here.

Tweaked lots of gameplay stuff. Current game level is actually finish'able now, no more random endless fight-until-you-die (will be as separate mode though).

Improved overall game-feel -- now you much MUCH better feel when you hit the enemy, when your ship is hit. Energy-critical condition also communicated much better now  (it's obvious you're in trouble even without looking at energy-bar).

Visuals are prettier now, especially for environment.
Enemies are getting vanished/evaporated instead of generic explosion.