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