• Arrow Keys to move
• SHIFT to slow down
• Z to shoot
• X to bomb
• F2 to reset game
• F4 to go fullscreen, or toggle it in Options Menu
• ENTER to pause, and access Options Menu
• F9 to take a screenshot

• F12 while in Main Menu room to disable all text besides debug for background viewing
• Left/Right while hovered over 'Start Game' to pick stages/boss/test rooms

The word GMOSSE is an acronym. It stands for Game Maker Open-Source Shmup Engine. It serves as a swiss army knife of resources culminating in a perfectly playable shmup with all the technical features the STG community come to expect from such a game, and is also my personal playground for testing new features.

How a STG should be made is a balance between the interests of you as the developer, and the audience you're targeting with your project. I originally wrote this project in 2011 with features that were in vogue at the time and with quite a few influences, but in hindsight the game could be a lot more entertaining. It's an engine demo first, good game second, subject to change.

Ideally the latest one (as of writing GameMaker v2024.4). There is a legacy branch for those interested that contains the last commit of the project when it was still operating on Game Maker Studio 1.4.9999.

Apologies, I do tend to commit checkpoints to the main branch as-is, so for stable learning tagged releases are the way to go! (there aren't any yet, but there will be when the dust settles :))

This project would not have been possible without the fostered environment of the Development section of system11's Shmups Forum.

GMOSSE makes use of multiple assets provided by members of said forum and the wider community as a whole. Shout-outs to fellows past and present:

• Kaiser AKA JackDarx - Invaluable suggestions towards project, awesome sprites, long time friend and co-dev!
• Rozyrg - contributed a lot towards GMOSSE discussion wise, showed various alternate methods of doing things
• railslave - composer for GMOSSE's music
• S20-TBL - contributed heaps regarding attack scripts and bullet behaviour CONTRA YAGAWACORPS EXPLOSHUNS BY MICHAEL BAY!
• GodHand - coded basis of S20-TBL's circle attack scripts
• Emerald Master - Alternate awesome fonts!
• EddyMRA - posted his spread shot script from Xeno Fighters R, and inspiration for various functions. Even Xeno Fighters R in itself was an inspiration
• worstplayer - helped out tons in original 'TATE in GML (Game Maker)' thread using views/surfaces
• MegaGamer - neat scrolling text engine in Game Maker that I could understand
• iluvfuz - GMLBuddy helped me tons in getting started
• DrPetter - sfxr (for the neat shmuppy sound effects)
• Nimitz - Excellent joystick support (once I fixed it and added configurable deadzones :P).
• YoYo Games - Well, you know, GameMaker, etc.
• DJ Incompetent - Tested the game as the sounds got reinternalised
• MathU - Keyboard control customisation advocate, reminded me to get onto adding this function!
• mjclark - Joystick testing with him was very helpful for Development and inspiration from doujins!
• Pieterator - Developer of Aero Flux, solution to TATE distortion bug & various helpful advice.
• trap15 - Explosion flicker idea, testing for VirtualBox and WINE

If I left anyone out, please let me know so I can add you to the list.