An old game (I can find apps from 2011) with a far worse AI than others (comparing it to 'Ten' on iOS). This one just handed victory to me. Fill the central board and you'll get a lot of free placements (even if you just need one more move).
The AI for the first-time player is easier than the usual. But I'll add a difficulty selection option.
And perhaps, not 2011, but 2013 - that was the date of the famous post at Math with Bad Drawings
Fire aura seems to be broken. If it deals 0.5% of max hp as damage per second, anything should die nearly as soon as it comes in aura range (as they've lost over 99.99% of their hp by then), but I don't see that happening. Would make non-insane mode impossible to lose though if it worked like expected.
Fire rate + range + darkness (+void) + ice + piercing = win on easy/med/hard. The darkness effect changes the difficulty scale from exponential to linear (as the damage scales evenly with the health). Ice + range gives me all the time I need to kill enemies 1e100 times stronger than I am. The difficulty should increase exponentially like it did when I just started playing. Waiting thousands of waves till enemies get close is just boring. Even if they do hit me, I still have 99% chance to survive (unbreakable and others).
Playing on insane: the base enemy health is 1e33 times higher than my base damage (GY=1e33) and their attack is more than my max health squared. Why am I still alive?
Small balancing issue: normal abs resistance is weaker than elemental abs resistance. Therefore purification is sometimes not desired, especially since (on medium) the elemental abs resistance is more than the enemy attack and the normal abs resistance is not.
Insane darkness enemies won't become visible if they are hit by the purification effect before becoming visible. They can attack my tower and I can't shoot at them so I had to wait till they 'vaporized'.
The insane-nature enemies are just stalling the game. While completely harmless because of the offensive air upgrade, I can't kill them because they are fully regenerated before they come back on screen. They just need a serious missile and in meantime I can't go to the next wave becaues of 50+ enemies. Some survive for 10 rounds before being hit by a serious missile.
The perfect tower... I've extended it with a 7 blocks high stack of enemies on top of the tower :D (high health + 2m range nova)
http://i.imgur.com/ZvnEB9f.png?1
Just an idea that will drastically change game tactics: 1. increase the rate at which max tower health increases. 2. Massively decrease the regenerative abilities (by at least a factor 10, the tower should not fully regenerate before the next attack comes). 3. Decrease the knockback effects by 1% (multiplicative) per 10 waves. 4. Change the progress pause treshold from 20 to 50 enemies (or remove it completely).
This will need further refining, but it should make offense aid in defense as ofensive upgrades generate more time to regenerate before the next wave comes. At the same time it makes elemental defensive upgrades useful as non-universals can finally reach the tower.
I'd like to see an options menu on the main menu or at least the number format dropdown in the town. Right now I have to go ingame to change the number format to what I'd like to see in the workshop (which is 'normal') while in-game I prefer normal for the early waves and engineering for late-game.
Quite often a pre-selected enemy comes into the playing field. If I want to select it I first need to deselect it by clicking somewhere else. To reproduce: select a boss enemy, kill it and don't click anywhere else. 20 Waves later the boss appears with a red circle around it. Cause: Enemies in the enemy pool remain selected and return in a selected state. To fix: deselect enemies on death.
The visual nova effect is 85% bigger than the effect radius. Easily noticable with nova radius upgraded to 10m. Enemies on top of the tower (consecutive gravity effects) aren't affected by the nova (or not noticable).
 "Strategic Tic-Tac-Toe"){kind=icon}
 "MazeEye"){kind=icon}
 "The Perfect Tower"){kind=icon}
The AI for the first-time player is easier than the usual. But I'll add a difficulty selection option. And perhaps, not 2011, but 2013 - that was the date of the famous post at Math with Bad Drawings