Some final polish, bugfixes and optimisation. 

Additions

•  Added an additional starter level so people know how to use land controls before needing to swim

Removed

• Removed *ahem* "Deathium" as a possibly spawned pixel

Improved

• Grass is now integrated into the simulation, previously it was just a sprite
• The hose now unloads it's physics segments when out of render distance, previously it just dangled over the void
• The player's backpack has a texture now
• Pixel colours are now more vibrant
• The hose is darker and blends in better with the background

Balance

• Made some levels slightly less unfair
• Damaging pixels no longer destroy the player in 6 frames
• The player character checks pixels more reliably

Optimisation (Around 200% performance gain)

• Textures only update when something visual has changed, previously all pixels would update
• Pixel colours are now stored in byte instead of float 
• Textures are written to the GPU more efficiently

Bugfixes

• Pixel pipes now generate pixels in the correct range and not outside their block
• Drain collision box fixed