Here is the full list of all 20 Globat Pixels achievements.
Kill 3 enemies with one shot
Change weapons 12 times in one life
Change weapons 12 times in one game
Kill 7 enemies in one life with the homing bullet
Kill 5 enemies in one life with the bouncer
Play the Eiffel tower map
Kill 3 enemies in one life with the particle ray
Use 4 weapons in one game
Kill an enemy with the particle ray
Kill 2 enemies with one shot
Kill an enemy with the shotgun
Win against AI with maximum difficulty level
Win against AI with maximum difficulty level whilst only using the bouncer
Play the Taj Mahal map
Kill an enemy with the homing bullet
Survive 40 seconds without shooting
Score the last point whilst playing with an ally
Die 15 times in one game and still win the game
Kill 5 enemies in one life
Kill an enemy with the bouncer