If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Sabotage the alien base from inside. Collect enough explosives located in different sectors of the base, to destroy the main power source of extraterrestrials.
W,A,S,D / Arrow Keys - Move.
Z,L - Boost.
Spacebar - Shoot.
Enter - Open door.