Nice game! Worked well on windows 10 x64. Though after about 5 minutes of play where I just drove around the monsters incessantly firing I achieved a score of about 27,000 and then the game crashed. Perhaps it ran out of memory? I fired both left and right cannons non-stop so if the bullets, blood, tracks, monsters and bodies aren't disposed of, it may have overloaded the JVM memory limit.
The top-down view and effects are great. I especially like the car track effect, very satisfying
If you had time to add more weapons and a hot-seat co-op game mode where one person drives and the other shoots, perhaps with the mouse, it would be cool.