There used to be a little arcade called Casino Leisure Centre, just around the corner from Goodge St. Station in the middle of London, sandwiched between Computer Exchange and a Scientology Centre. A group of shmup enthusiasts called the Casino Crew that we were members of met there every week, and as a joke we made a micro game about the arcade and its personalities: "Casino Caravan Collection". Everyone liked it so much that we decided to make a proper game, one that could be played seriously for score, worthy of going in an arcade.
We both agreed that our next game should be a shmup, and began by making a list of scoring systems in other games as inspiration: we wanted a system that didn't ruin your run if you died, a simple core mechanic that you could jump right back into regardless of where you were or how many lives you had. Other essential features were a minimalist, easy to read HUD, screen rotation for vertical monitors and a scanline filter.

There were a number of different concepts including a traditional space blaster, but we soon settled on "Bitter Moth": the premise was that you would play as an ugly moth that was bitter about his bad looks, and would "soul drain" the colour and life out of pretty butterflies and other insects, making them wither and die. Rapid shot would "soul drain" the enemies, switching to laser would finish them off for a bonus. That was the basic scoring, and it would have a visual representation of the system that wasn't just a large number.

We quickly discovered that this would be a nightmare to animate, as every enemy would need many versions of each frame to show them withering. More importantly, it wasted memory and made the game look drab. We then changed "soul drained" enemies to have a Tron-influenced neon look instead, which needed less frames and is much more interesting visually.

All the backgrounds were designed, drawn and coloured before being put into the game engine. We then found they were too large to scroll smoothly on older graphics cards, and needed to be broken into tiles. A system for breaking them into tiles, as well as loading, unloading and scrolling the tiles was coded. After all this the backgrounds were desaturated slightly to avoid colour clash with bullets and enemies.

We then worked on enemy placement, generally starting with static ground-based enemies because their positions were largely determined by the background layout. We'd both played a lot of shmups so had a good idea of the pacing that we wanted.

We would meet in a coffee shop with the game on a laptop, work on one stage at a time until we had something playable, then progress onto the next stage until we could play through every stage back-to-back. Then we would go to the beginning and refine each stage in order, polishing it more and more each time.

As the game progressed we kept on adding ideas to the scoring system, so for a while we had a small helper - the Broken Butterfly - that would follow you around. It did no damage but constantly "soul drained" enemies. During the middle of the game's development we considered having bullet grazing, but didn't actually add it until much later. Eventually we decided to just have "soul draining" and grazing, with hidden items to find to add variety. We had many other ideas that were interesting by themselves, but when added together just made the game too complicated.

The Casino Crew helped us along the way by play-testing the game, being brutally honest about what they thought! This was incredibly valuable for us, and we spent ages tweaking enemy attacks, damage, speed, placement, HP and more by the smallest amounts. Eventually we got to the point where we could no longer distinguish if we were just making the game different rather than better, so it was time to release. At the suggestion of one of the Casino Crew members we also changed the title from "Bitter Moth" to "Space Moth", which everyone agreed sounded better.

All the graphics were done in Photoshop using a Bamboo Tablet, and everything was made at a resolution of 320x240 then doubled in size before being added to the game. All the music was done in GarageBand on an iPad, with a few overdubs using the Solina String Emu. The original game was coded in Flash using AS3, then moved to Stencyl and finally GameMaker: Studio using GML.