There was game I used to play long ago on Amiga.
Exactly same concepts..
The title was.."Walker"
You made nice altered version..but..it needs more balance.
Even at old few bit game, overheating wasn't this insane.
Consider doing something with it.
Good, the graphics where great, the powerups where very good (But a litle scarce further into the game). Did get a little laggy once the helicopters started dropping all the rocket guys. And without any powerups, (as I said they get quite scarce) my gun just wasnt cooling down fast enough to cope with the miss's caused by the lag and hitting the enemies.
Loved the giant robot and shooting everything.
The overheating is killing me though.
The graphics are amazing. I'm impressed, but the gameplay is kinda boring and when I click 1,2 and 5 the rbotm won't shoot anything...
Basically a less violent Walker.
Very simple entertainment, with no real point to anything, just like good old Walker for my Amiga 500.
However, Walker had blood and gore. This does not. ;_;