Not just storage upgrade cost glitches (negative etc, then 0), research upgrade cost behaves the same way, and research/second glitches to small values like 100/s->101/s->102/s etc, ruining the game.
Great game! I did not finish it yet (what if it's already present?), it needs some random mode too, where game mode changes after a few lines (unlockable at a star on each level or anything like that).
Not nice when it hangs (game itself: music is present, but picture is still and controls do not work), and on restart you start from the first level.
Lack of UI (selecting level etc) is not a cool style, it's inconvenience.
Losing upgrades on completing level is a nice feature: you do not get easier game for playing good and buying upgrades. Lack of alpha blending does not ruin graphics. The game is not good anyway though.
I do not have enough money to buy the shield to get the last badge.
I played quite grindy and did not waste money on healing items (though I bought health/mana permanent boosts), and I bought exp elixir like once.
Completed arena twice.
So now I have to complete it twice again to get enough money.
I think it was a bad idea to require buying all items to give a hard badge to a player who completed the game. (Completing bestiary should have been enough.)
The game is too easy or short though. For being a "time-waster" it should have hundreds of levels or some kind of random levels. The only level requiring some thinking was level 4:)
Got to level 77 too. It's insane: mostly grinding level 15 for diamonds and everything (it's not that boring anyway, compared to other levels). The cost of upgrading Dodo (the last green bird) to level 5 is 339 diamonds (or 4500g600p).
Cool effects! Enhanced version would better have more different graphical effects to be not boring. Just more "puzzles" with the same looking buttons won't be great. Higher contrast may ruin everything, it would better be optional.
One star because
1. It's skill denying (possibilities are very limited, luck based)
2. It lamely tries to beg for money (or "extort"?)
Energy alone could make it one star too, but other ways of trying to get my money are not better.
I completed the game before. Now I do not get badges. Having completed stage 5 again I did not get medium badge. Do I have to complete all levels anew to get the badges?
 "Unpuzzle"){kind=icon}
 "Spidle Tridle"){kind=icon}
 "Beam Ball"){kind=icon}
 "Idle Hacker"){kind=icon}
 "Bobo's Trouble"){kind=icon}
 "Busted Brakes"){kind=icon}
 "String Theory"){kind=icon}
 "Dragons Adventure 2"){kind=icon}
 "Hero's Arms"){kind=icon}
 "klocki"){kind=icon}
 "Fillz"){kind=icon}
 "hitBox"){kind=icon}
 "BravoBirds"){kind=icon}
 "Lost Ethereal"){kind=icon}
 "Five amigos IDLE"){kind=icon}
 "Evo Explores"){kind=icon}
Mmm... you can try to hit helicopter when jumping. Some kind of boss :)