First few days are important. d1: balloon, d2: employee, d3: music, d4: employee + menu, d5: employee + lights, d6: cleanup, d7: singer + bushes. If you don't get the $50 bonus each of these days, just start the level over.
Strategy: First try to open a few chambers quickly, maybe 5 of them. Then start reading some random text from somewhere, like another browser window. And type the words you read as fast as possible without thinking. Trust me, it works.
Every time you visit Upgrade, your balloons healths resets. So you can keep going up without losing a single balloon. I got bored after 50k height, nothing new happens.
2 important tips:
- when it gets too fast, hit the boxes to slow down. it makes the game easier.
- the longer you hold the jump button, the further and higher you go. make sure not to make too big jumps over small gaps, or you might miss the next one.
good game but:
- some skills are really crappy, so u never get them
- game gets easier after lvl 50 or so
- traps are usually not worth it. and you get xp bonus for not using them
 "The Last Frontier"){kind=icon}
 "Diner City"){kind=icon}
 "Clockwords: Prelude"){kind=icon}
 "The Tickler"){kind=icon}
 "Higher!"){kind=icon}
 "Canabalt"){kind=icon}
 "Medieval Rampage 2"){kind=icon}
 "Knightfall 2"){kind=icon}
 "Antbuster"){kind=icon}
 "GemCraft chapter 0"){kind=icon}
 "Max Damage"){kind=icon}
 "Cube Colossus"){kind=icon}
 "Desktop TD Pro"){kind=icon}
 "Wizard Defense"){kind=icon}
 "William and Sly"){kind=icon}
 "Get Off My Lawn"){kind=icon}
 "Friendly Fire: Blood and Gore"){kind=icon}
 "Heavy Weapons"){kind=icon}
 "Pwong 2"){kind=icon}