Thanks for double checking and letting us know!
We try to make our games accessible to multiple input options, including mobile, keyboard only, and controller. Not all of them work out well, but it does affect our design, and sometimes limits what the mouse can be used for. We plan to add additional weapon options, and will think about perhaps adding one that allows aiming with mouse/right analog/keyboard, if we can work out a good UI for mobile that still makes it easy to fire all 3 weapons.
We did limit the upgrades partly based on the enemies we had implemented. More energy and faster energy regen will be among the first upgrades to be boosted once we have more enemies to fight.