I should have posted something here much sooner. Usually, a first post will only have a basic idea or a bare-bones demo. Those stages were past a LONG time ago.  I would estimate the PC version of IMPACT is currently 95% complete so I can release a demo in the not-to-distant future.

The idea for IMPACT came while helping someone with a snooker/billiards simulator they were making. I had a crazy idea about making the table slope down into a hole in the middle of the table, kind of like a wormhole. Balls would make several graceful loops around the center before shooting down the hole. I set up auto-spawning balls and used another to knock them out of orbit and off the screen. It was quite satisfying, but lacking something.  It needed a sense of danger.

In a flash of inspiration, I changed the orbiting balls to asteroids, and the hole in the center to the Earth. Let too many asteroids hit the Earth and it was Game Over. The core of the game was born, as was the name - Impact.

Lining up your "shot" was slow, and did not make gameplay sense. Controlling a ship to nudge the asteroids off-screen, did. After careful consideration, I believed that launching the ship from the moon would be a more practical and logical option than launching from a space station. It also left more playfield space for the black and white holes to orbit.

Using the black holes to teleport you, asteroids, and other things to the white hole created an exciting dimension to the gameplay. As did the homing UFOs, especially when I added the space mines for them to drop. While they only affect you slightly, asteroids could be flung anywhere, including at the Earth. Take too long to get rid of a UFO and you can get overwhelmed with mines, leading to asteroids pinging violently around the screen. Definitely a pulse-racing experience.

Playfield littered with space mines

Early on I decided that rather than having to clear all the asteroids to finish a level, they would be time-based. So early in the game, you will be more likely to get a brief break between them, yet as you progress you will struggle to clear the last of the previous level during the start of the next. Gameplay goes from easily achievable levels to a near-relentless onslaught. Even the decision to have every fifth level be a chance to refill the shield becomes an increasing struggle to survive.

For quite a while that was it for gameplay. Instead, I worked on the sound effects, music, and title screen. Originally I had intended Impact to look and sound like an early arcade game but soon decided against low-res pixel graphics and bleeps. It did not feel right. It needed more detail and proper sounds.

For some of the game's graphics (the Earth, spaceships, asteroids, UFOs, space mines, satellites, and intro corridor) I used free assets on the Unity Store. The rest I drew in Gnu Image Manipulation Program (G.I.M.P.) Some sounds (explosions, stones being hit, metal clangs, electric fizzes, and firey hisses) were found on Freesound.org and then modified in Audacity to fit. Other sounds like the comet roar, UFO alert, magnet attracting, etc. were generated entirely in Audacity.

The music has changed significantly since I started. My original idea was for interactive tracks dependent on what was happening on screen. 16 separate tracks - Bass Drum, Hi-hats, Rim shots, Snare roll & cymbals, Bass drone, a few bass lines, and several synth parts - some only coming in when certain objects, or more than a specific amount of them, were on screen. For example, an urgent string section during a UFO attack, or the bass pattern getting more intricate with more asteroids on screen, both adding to the sense of urgency. If each level was longer, and had a more standard "clear everything" ending to them rather than being a fixed time, then this might have worked.  In the end, I took those original tracks and arranged them into the music for levels 1 to 5.

From the beginning, when I chose "Saving the Earth" as the objective for the game, I knew I wanted to incorporate a two-player option, similar to classic arcade games. However, instead of having players take turns, I envisioned both players being on the screen simultaneously. Initially, I only considered a player versus player mode, but later realized that including a cooperative mode would allow experienced players to assist newcomers and help them progress further in the game.

By now I knew it needed more variety  so more hazards were added:

• large asteroids that split into four smaller ones
• comets that nudge everything else out of the way and can not be stopped
• bonuses that are launched from the moon to replenish the shield, booster, and repulsor
• a radioactive cloud that saps the booster and repulsor
• and cosmic wind that blows things around

Gameplay was balanced to allow for the new additions, but I was starting to feel uninterested in the music that kept repeating every five levels, especially since I was able to clear thirty-five or more on a good day. To change things up, I used the same instruments to create different variations of the melodic parts and rearranged them. As a result, there are now new "themes" to listen to every five levels until level twenty where it starts over again, at least for now.

Some new players found the initial difficulty level, which I considered easy, to be discouraging. Therefore, I have added some options to cater to different abilities. You can now select Easy, Medium, or Hard. Personally, Hard is quite challenging for me, whereas I can complete over thirty levels on Easy. A few players expressed their inability to finish the first five levels on Easy and suggested the option to skip levels. I felt this would break the gameplay flow. As a compromise, players can now start from levels 1, 6, or 11.

Having a single high score for all possible combinations of difficulty and starting level seemed unfair, as it had been a feature for quite some time. To address this, nine separate high-score tables were introduced, each corresponding to a specific combination of difficulty and starting level. While this may seem daunting, it provides players with a greater incentive to play again and strive for the top ten spots on each table. In essence, this gives players nine opportunities to be the best.

So why no demo yet? 

Bugs. Only a few minor ones, but my OCD will not let me release one while I know they are there.

The big problem is inconsistent game controller support. Although you can customize the keys for each action and assign functions to specific buttons on the controller, it currently displays the button number (e.g. button 1) instead of the actual label (Square, A, X, etc.). The buttons for firing the booster and repulsor change position depending on the type of controller used. I think I know how to fix it, but it means completely recoding the input system. A big job that will take time I do not currently have, and will probably create new bugs. And I hate bugs.

When I do release the demo it will only be the first five levels and on Normal difficulty with the minor bugs fixed.