This was my very first gamejam, I joined since the jam was solely for GM devs and the theme was quite open/simple to get around.
I put ~16 hours of actual work (plus some hours researching for GM functions, background art, music and generating the sound effects) and did the bad decision of working overnight (I'm 39yo and not in good shape so this was a bad idea overall)
I had not a single template to built upon,so code/design wise I start from scratch. Kudos to the amazing artists from itch.io from whom I took their assets (music and backgrounds) (I asked for permisson or they explicitly allow it on the description/license).
I may have got a bit ambitious building upong power ups instead of focusing on a single game mechanic.
At least you play several times is hard to get used to the diff weapons each enemy gives you, I thought about giving the player some visual cue but couldn't come with something. It's a gamejam so whoever is playing the game won't play for more than 5-10 minutes at least is having a lot of fun.
Maybe a boss fight wasn't needed. The Boss Fight wasn't supoosed to be that chaotic but I didn't have time/energy to balance it as I've wished. Even the simplest idea/theme can get out of hand.
A diff kind of shoot'em up may have fit better instead of a "horizontal scrolling" (there's no actual scrolling), maybe one in the line of Asteroids.
Edit: after some feedback 2 main things were missed a reload mechanic in case you ran out of your 1 only ammo and some invisibility timeframe when continue after gameover, I totally thing those 2 mechanics would've made the game feel much better.
Edit2: There's a design flaw/bug, whereas a bullet is outside of the room automatically set your shot type to "none" even if another bullet destroyed an enemy (like when using the double shot)
As non-english speaker I'm having a hard time between using shot&shoot.
Also technically I learnt some things I didn't know about GM and which turn out to be quite simple to do (I've been using GM for the past 6-8 months, so even when I have some experiencie with programming, it is not my daily job).
I had a clear idea right from the beginning, but 1 thing is to have an idea and way diff world is to expand that into a whole game, speciall based on the genre you choose for it.
I went for shoot'em up (kind of Space Invaders) with horizontal "scrolling" (there's not actual scrolling the ship is static on X and enemies come to you but that gives the illusion). because was the simplest thing I could have done, after the gm is over I think this was a good decision.
As theme was "just one" I went for just one shot, the gimmick was that if you destroy an enemy you will be able to shoot again. Also based on which enemy you destroy you will get a diff type of weapon/shot, I also feel good on this matter.
My idea was to make some sort of rhythm game/shoot'em up, where you will use each diff weapon to destroy next enemy and so on, (sometimes with enemies positioned (on purpose ) in a way that will make you fail.
I got to give a good feeling on that but only for a couple of times during the gameplay.