This is a brilliant game!
The feeling of the movement and the aiming is slick, together with the way enemies move and projectiles fly is really smooth, it feels good. Overall, you've done sterling work with the physics. The look is great, unit design, explosions and the aesthetic, every bit is in sync from the HUD/UI, to the menus. It's really nice. The sounds too are excellent. I got nothing but praise for everything you've done.
If I can offer some feedback, which you can totally ignore and I'd still buy and love the game:
I saw that at the moment level score is determined by time and hits taken. I wonder if public damage will sometimes be a factor too? I don't know what your intention is yet with overall lore etc. but maybe depending on whether you'll go down a different factions path, and whether the missions become something akin to contracts one takes, and money won in order to buy equipment, where a fight is held could determine whether you need to be more careful with the collateral damage or will actually earn more the more damage you cause.
I saw that you intended to make the railgun a late game weapon because it's very powerful, which makes sense. I quite liked the need for perfect accuracy the gun required, maybe a heavy sniper rifle could be cool, one which fires instantly but has a slower reload. Maybe more semi-automatics or single shot weapons.
I'm not sure what else you've got planned but maybe a bit more intel going in regarding units could help you make the equipment choice.
I wonder if it would be cool to have different forms of boost. Like one where if you double tap a direction you do a sort of small power slide or shunt. Maybe there could be a slot for different evasive modules/equipment (when that helicopter's coming for me I'm terrified - love it).
The smoke grenade is excellent, also the spread and visualisation of the trajectory is just superb. I used it a lot to get the jump on a bunch of static heavy units often. That turret that shoots them out the sky is a pain in the ass, I love it, it forces different approaches, well done!
I really like the variety of the missions so far, the bug level was great, I really tried to not destroy the garden at first but things got desperate towards the end, and it's great to see the flame thrower shine (I liked the surprise of facing a different enemy species/group), and the last level where the speed with which one tries to eliminate the targets in order to not have reinforcements called in was great!
I really liked this one moment where I was caught amongst some parked cars, and I had full health so I can only imagine that that little grunt had hit the cars which blow me sky high. Great stuff.
I'm sorry, I got carried away.
Can't wait to see what you do, you've done excellent work so far. You're very talented.