UPD: New version without player lives. Just saves at savepoints.
You can use the slow motion ability for accurate shots and quick weapon switch. Each weapon is more effective for certain enemy types and less effective for others.
Game trailer is here https://www.youtube.com/watch?v=BmLKYChtGu0
Controls:
LEFT & RIGHT ARROWS - Run
UP ARROW - Jump
C - Fire
X - Slow mode
Z, V or 1..7 - Switch weapon
I - Information
P or ESCAPE - Pause/Menu
M - Mute sounds
R - Restart level (when paused)
K - Define keys (when paused)
PLUS & MINUS - Volume
You can double jump when you have it.
When you pick a jetpack, press jump 3 times to fly.