Very nice mech shooter game. Reminds me of Cosmic Break, Daemon X Machina, and Armored Core. However there's not a lot of horizontal mobility for the mech, making it feel sluggish. I suggest adding in a boosting/sprinting system that utilizes the pre-existing boost bar. Not sure about the ammo system. The weapons runs out of ammo too quickly for me. Do you intend to add ammo pickups or is it going to be a "lots of ammo, no pickups" type of deal? The feedback from receiving damage doesn't feel enough for me. I missed out instances where i get damaged and i've died as a result.
Something that would benefit this game is the addition of melee attacks, either in the form of a quick melee button or dedicated melee weapons.
Other than all of that, i think this game shows promise. Looking forward for more.