There was some value to this as a time killer at work. Some of the incremental satisfaction is there, but not enough. Visual feedback could be better. Having no animations for the enemies does hurt the visual appeal, and they are pretty boring overall to interact with.
This game has sort of a "theoretically" good foundation, but, for me to keep playing, needs a bit more to it. The fact that you didn't capitalize on mech customization in a mech game, honestly, feels pretty lazy.. like at least give me different weapons to play with.
HP upgrade didn't matter at all as the enemies, even bosses, didn't ever make me feel like I was going to die at any point.
This game is as basic as it gets for incremental games - it's clear that you're trying to capitalize on a current format of incremental, and in a sea of an oversaturated genre.. I wouldn't go any further with this unless you had some new ideas to add to the genre.
If this was your first game or one of your first, it's not bad.. but as I did come to this from a dev log about how you're putting this on other platforms, I wouldn't if this is as far as the game goes.