Howdy! Noticed the lil' bit of updates you've done with the game so far and I think that it is coming along pretty nicely with what changes there've been. My only feedback/criticism right now I'd have comparing this game from when it was first uploaded and what it is at current is that if you could perhaps make an option in the Settings to switch/adjust particular effects that affect the game's performance. My computer isn't a toaster per say, however, I have noticed that the movement is a tad less fluid now due to the slight of changes. Just my 2 cents in though.
EDIT: Also wanted to remark that you've done a pretty good job with rebalancing the weapons and upgrades on this as well as the enemy AI. Keep up the great work on this!