Btw, tips:

• Watch out for one-off buys. Like gems, you can get maybe 20 in the first day, but I blew the first 10 on something I didn't realize was a one-time boost. Now I don't know if I'll ever get enough for +100% Bounce! The game wants you to purchase them, at least on Kongregate.
• from Kongregate comments: "If the cost of density is less than half of the meta-energy you have then upgrade density. If the cost of gravity is less than 1/10 of the meta-energy you have then upgrade gravity."
• I have yet to figure out of there is an "ability" that gives a longer-term boost.