Did you use Proguard, Pack200, Kzip and Zip2Gzip, i.e. Riven’s compressor tool chain, in order to get your final jar ?
Yep. Well, I used groboclown’s ant tasks, but I think they’re virtually the same.
The UI and command set are really the stronger point of your game. Concerning the gameplay, I wonder how it would become if the action was twice as fast. Indeed, I especially regret that the beginning of each level is a bit slow.
Can you tell us more about the upgrades ? Is the one with a triangle related to speed or attack ? And the one with a shield symbol, is it only related to defense ?
The triangle is speed, which boosts worker speed by 50%, and the other one is an armor upgrade, which gives your units evasion - it was easier to implement with few bytes than unit hit points. 
I’ve considered making the upgrades yet more expensive, considerably stronger, and making the user retain them when switching maps. Not sure yet…
On start all unit move very slow. Is it like that or something wrong with fps, I dunno.
@ReBirth: Difficult to say without seeing it… just how slowly are they moving? They are indeed quite slow (maybe too slow), and their speed can be increased in later levels with upgrades. However, it shouldn’t be so slow that it’s not playable…
Then I guess it’s not frame rate problem, since the units move as I click (quite responsive). I’m just too impatient.