This had great potential but you didn't achieve it
You really could've done a lot more with the story, gameplay, and generally polished it more, but you didn't, which is a real shame. Maybe it's because I study game design, maybe it's because I have a horrible affliction called "standards" but to get an "OMFG AWESOME GAME ILOVEU" response from me you'd need to fix a few things;
First of all, the story:
VERY interesting story, at the start. There are only 2 problems with the story, really. You didn't include a drive, and you didn't include an ending (it's kind of obvious, but I'm just highlighting what's important). Basically, it seems that the story started and finished and this is just a minigame epilogue to pad it out, except that you didn't include any 'game' in the backstory (that isn't a problem so much, the point is that it just seemed pointless in terms of story). It felt like there was no point whatsoever, And not having an ending made it moreso. Which group of robots am i representing, what am I supposed to be achieving, and why? Why would Judgement city be so important? Are robots sentient in their own right, and act just like humans? Maybe You're the last human alive or something, and [reasonGoesHere] (blah blah blah, come up with a story on your own then put it here. replace the 'last human alive' if you like).
Then the gameplay:
It was really, REALLY unpolished. from the tanks seeming to simply slide sideways when going vertically on roads, to the 'wall' being in the wrong perspective (were you going to make a horizontal wall, then just use the sprite fr a vertical wall after rotating it 90 degrees?), although technically they're both simply graphical, to the "spambot" nature of the game, the hard-counter EMP (you don't wipe out every single unit on the field, EVER, maybe make it wipe out all units on your side of the field and damage the units on the other side, and damage all of your units or something) and the incredibly slow-pace and lack of challenge (but don't force extreme challenge on players, EVER, make sure the average player {in your targeted audience, which in this case would be whoever goes on newgrounds} can pass a level with no retries, assuming they're trying their best), not to mention the lack of original units (average, fast weaklings, [literal AND metaphorical] tanks, medics, maybe the lightning unit might've been useful but it was situational at best and was never, ever necessary).
By the way, the survival REALLY DOES need work (ramp up the difficulty, make sure the ending doesn't stay forever surviveable, the "don't force extreme difficulty upon players" doesn't apply here unless you force the players to play endurance or you make endurance a requirement to advance the story), when I was playing "endurance" I left it for 20 minutes or something and now i have 40,000 money. I also left it on while typing this, it's impossible to lose accidentally (unless you do something really insanely stupid, which I don't think anyone with an IQ above 80 could achieve accidentally).
Now, the doctor* prescribes a full set of vigorous playtesting and a healthy diet of not interfering with playtests and actually fixing anything which all the playtesters hate. Here's some help so you can get some decent playtesting going:
(these are links for info on playtesting)
P1: http://www.gamasutra.com/view/feature /3963/the_silent_revolution_of_.php
P2: http://www.gamasutra.com/view/feature /3985/the_silent_revolution_of_.php
http://creators.xna.com/en-us/playtes ting
http://www.gamecareerguide.com/featur es/503/pro_game_dev_tips_play_.php
Last up, this article is the most directly important (if you have to read one, read this, and read all of it):
http://www.moddb.com/games/digitanks/
news/video-and-playtesting
Now, go achieve that potential.
LEGAL DISCLAIMER: THE FOLLOWING DOES NOT REFER TO MEDICAL PROCEDURE AND THE READER CLAIMS FAULT IF THEY ACCIDENTALLY KICK THEIR OWN HEAD IN FRUSTRATION OR SOMETHING EQUALLY DUMB