This "memory leak" issue seems to be coming from just one or a few levels, in the 1st third of the game. To get past it: play a level, get your all your rewards, do your upgrades, back ALL the way to the main menu, then restart. That way your game is saved.
I grinded the 1st few until I leveled everyone up about 2 ticks, which allowed me to blow through the next bunch quickly, while maximizing rewards. I stopped noticing the bug after about halfway through but, of course, your mileage may vary.
The attackers have developed interstellar travel but, lucky for us, their ships don't have laser beams. They aren't even smart enough to drop a wrench to defend themselves. Awesome! 6 stars!
What I don't like about the other parking games is that they use dark colors and little or no music. This parking game uses bright colors and a pre-recorded guitar rock loop. It is the best parking game, for these obvious reasons.
And the icing on the cake, so to speak, is that you can't possibly screw it up - just click where you're told and everything will be ok. The soothing music will help if your girl nerves start to break.
Dude, you made a game, and you get like 10,000 more points than anyone who hasn't actually made one. So good on ya, mate! But yeah, continue to develop, for sure.