Thanks to everyone who left feedback on the previous version of this game!
I've done some serious overhauling and incorporated many suggestions.
Goal: Clear each level by eradicating all the enemies with your small arsenal of weaponry.
Weapons:
Slot 1: regular missile
Slot 2: laser
Slot 3: homing missile
Slot 4: nuclear warhead

Key Additions:
-New power-ups! You can now freeze time and get massive speed bonuses
-New enemies: Watch out! Some enemies are now armed with homing missiles
-Shields! Hit the down key or the s key to activate your shields. Shields can only be used if they are fully charged and recharge quickly when not in use. the blue bar on the bottom left of the screen shows shield levels.

Scoring:
Points are awarded for kills and power-ups collected. Large additional bonuses are added for accuracy and speed.

Hints:
-Huge accuracy bonuses can be achieved by using the nuclear warheads to blow up multiple enemies at once
-There is no penalty for retrying a level. You can retry any level as often as you'd like and you can access all unlocked levels from the level select menu