What is this game trying to be? A side scrolling shoot 'em up with platformer elements? Odd. I like it.
What I don't like, however, is how little the game actually can give. The upgrades aren't satisfying, audio is a sad loop, enemies become very stale very quickly, and there's zero challenge in this game - failure only results in score decrease, and nobody gave a shit about score even when it was a thing.
The controls are very awkward. Anyone who ever played both shoot 'em ups AND 2D platformers expects jump to be on the same directional pad as movement. Because jumping IS moving. It's logical. Imagine my (and many other players', I bet) confusion when upon pressing "up", instead of jumping I... throw a grenade? And jump is "space".
Okay, I see where you got the idea of space as jump. You see, this only works in 3D games. You know, those, where you have to use all cardinal directions to move around. Side scrollers need only two, though. That's why they have "up" as jump. Because while in 3D games "up" means forward, in a 2D game, "right" means forward. "Left" on odd occasions. It might still have worked though, but why different hands? Moving and throwing grenades with your right hand while jumping with left? Why? It's even more awkward! Why not use WASD? Why not mirror it to WASD if you prefer arrow keys?
But enough of controls. There's tutorial part, too. Every game with self-respect should explain the player how to play it. It shouldn't say "look in the description", that's the equivalent of "look in the manual". Everybody hates reading, that's why many Atari-NES era games were garbage. They had to be explained, because they didn't explain themselves (looking at you, E.T.) They were explained in the manuals. And nobody likes to read manuals.
Also, medals are so inventive I can hardly keep my head from exploding with awe. You get "Guns" medal for upgrading guns. Ooh, and "Lives" medal for upgrading lives. Mind = blown.
But hey, it's a learning process. You'll get it eventually, just keep learning from your mistakes.