Of course we remember ASCII art! [692]
Hell, I live it! Every single damned day. Well, in my mind, at least...
This flash reminds me on the surface of an old LOLLERCOPTER game, which was similarly ASCII-art based. But while that flash game relied on the humour of teh LOLs, this one just relies on... well, good graphics and gameplay, frankly.
One wouldn't THINK of ASCII art based games as possessing the potential for graphics, but I love the constantly turning treads of your little tank guy... the way he angles to the left and the right as you move him around, the way he gets all.. up in arms and angary when he shoots... but all queasy-looking and scared if he gets hit by any 1s or 0s (accompanied by a nice big 5-sided red asterisk, no less!)
Also, the angling and turning of the green 1s and 0s is far more involving than what most programmers probably would have attempted in making such a game (more of a marching back-and-forth Space Invaders clone). You've put a little twist on the normal Space Invaders motif, and I for one thing that change can be good, especially when there's been plenty of the old way.
The only things I'd ask for would be cooler explosions when you score a hit (or hell, forgo explosions and just have little ~~~~s fly out of the hits!)... perhaps a bit more colour than just the green enemies and red damage asterisk.... and sound (which others and yourself have already mentioned). That's it! Thanks for a great simple game, the best kind on NG so as not to lag up our crappy old computers!