Thanks for the feedback! Adding some vertical movement isn't too bad of an idea. I might limit it to the bottom 25-35% of the screen, for difficulty purposes. I like you suggestions to make the enemies a bit smarter, so I will try and do that. Adding randomness in mines just to spice up gameplay is a change I should have already done. I might make it so jets don't spawn from the exact middle spot every time, and the drills will have a random speed. I might add modifiers later in development, like an example may be "Asteroids: Asteroids have a random chance to fly onto the screen, +25% overall cash" Just an idea. I don't quite understand how I would implement upgrades in another way, because the game is suppossed to be heavily leaned into the upgrade system. If you have ideas onto how I should implement that otherwise, I'd be glad to hear.
The game is really suppossed to be beaten once, as I do notice the lack or replayability. That has been an issue I have been trying to solve for a while.
I absolutely love the idea of a overpowered jet, maybe on like wave 25 where you are close to Earth to give players a glimpse of what the game can be. I might add a Z for ability 1 and X for ability 2. because W and S wouldn't work if I were to add vertical movement. I have experimented with automatic shooting, I personalyl didn't really like it because of darts like Split with 1.5 second cooldown. However, I will add an automatic shooting in settings if you want it. I think spacebar could also be used for shooting so it can be a keyboard-excludive game (unless you use split or have the rebound upgrade, which make it so right clikc redirects the bullets toward your mouse. I might add a key for that, like maybe 3 or C.)
For the shop, I like the idea of having the jet grayed out if you do not own it. Going onto your idea, Maybe there is a text above the jet saying "Item not owned" and when you do have it, but when you do not have it in use it says "not in use" and if you are using it is says "in use". Implementing an auto-own feature isn't a bad idea either, so I will just add that.
I'll see what I can do lore-wise to add depth to the game. I was thinking in later updates like 1.66 that completing certain tasks unlocks entries in a lore book that tells the player about their mission.
This is incredible feedback for my first game . Thank you.