Best upgrade game on the site
The premise and controls are simple, it looks like another typical upgrade game in a sea of them, but right around the time I cleared the first level I discovered the gameplay could be a lovely balance of simple and deep. There's a pretty heavy luck factor but unlike most games with such it just added to the experience- probably because none the random forces were detrimental so I never felt cheated.
The achievements/medals provide both a fair amount of time pressure and something to do in the endgame for just a little while longer. I found the times after Britain to be all too easy as I ended the whole thing after eighteen days but that was also a rewarding experience, shattering the expected time records by discovering the secret to breaking the game, which didn't feel like cheating either since it requires a good deal of unrelenting skill. It's the sort of game that does an excellent job of setting its benchmarks just right. The prices, medals, fuel system in general, and upgrades are all quite fair (not prohibitively steep or laughably cheap) which is a huge factor in me wanting to replay a beaten game. I'm especially glad you saw fit to make the controls and engine almost immediately available, putting those way too high would've about halved my score.
I've a few specific things about the game to point out. My only criticism may not even be your fault since my internet was acting up the whole while but I've earned all the time medals twice over and I still lack Kenya's. Stalling was largely pointless since my speed never dwindled sufficiently without me making it but your achievements gave that somewhat of a reason for being, was still entertaining. The scores, sadly, are obviously hacked. People have scores of two days up when I'm fairly certain the game's mechanics require at least one day per city even if you have accumulated enough meters to skip it. And I'm not sure, this might also be amazing timing, but I also think the game shuts your plane's controls down once you hit six thousand feet. Gives me a nice feeling, as though I've pushed the game to its limits and it had to force me to stop. :P
Finally, for those of you wondering how the fuck eighteen days is doable, ride the windmills. Yes, this requires you to be close enough to the ground to cast a shadow pretty frequently. Sometimes you might have to use the engine. But if you can pull it off you'll see results immediately, be surprised at how well the first plane upgrade does, then just completely break the game after that point.