Hey, thanks for the review! FFFFFF requires all hex upgrades to be purchased (I just checked the code & didn't technically force the final hex upgrade purchases to be required for this to unlock, you'll just get the medal and not technically see white on-screen). This will really get difficult on the last hex upgrade due to the creep in costs. The game technically saves your current hex score as a number which you can see from the NG leaderboard for scores. If your score there rises above 16,777,216 (max number of colors able to be represented with RGB hex codes) you'll be at white/FFFFFF.

As I see the cost creep, I've made a few balancing adjustments just now to make late-game costs cheaper, base stats higher, and the first few upgrades a little more expensive.

hmm ok thank you!