[We're talking to this year's Independent Games Festival finalists, and this time Eric Caoili interviews 24 Caret Games' Matt Gilgenbach about Retro/Grade, a rhythm game and shoot'em-up -- played in reverse -- which is nominated for the Excellence in Design and Audio awards.]

Far from a traditional shoot'em-up, Retro/Grade has players guiding their spacecraft in reverse through stages where the action has already played out.

To prevent damage to the space-time continuum, players dodge lasers returning to the enemies that fired them, while also positioning themselves to "catch" their own reversed shots. Power-ups enable players to temporarily restore the flow of time and correct their movements.

Retro/Grade features rhythm game elements, in that the timing of all the shots are based off beats in the music. Players also have the option of using either a keyboard/gamepad setup or a guitar controller, the latter control scheme allowing players to quickly maneuver their ship through different lanes by hitting corresponding frets.

We spoke with 24 Caret Games' co-founder, game director, and gameplay programmer Matt Gilgenbach about Retro/Grade, nominated for both Excellence in Design and Excellence in Audio awards at this year's Independent Games Festival (part of Think Services, as is this website).

Gilgenbach discusses how the team stumbled upon the game's novel design, the differences between its two control schemes, and the need for publishers to fund innovative, low-budget projects:

What kind of background do you have making games?

Matt Gilgenbach: I’ve been working in the game industry for over five years and have worked on titles for Xbox, Xbox 360, PS2, PS3, PSP, GameCube, PC and Mac.

Before co-founding 24 Caret Games, I was the lead gameplay programmer at High Impact Games, where I worked on Ratchet & Clank: Size Matters and Secret Agent Clank. I also worked at Heavy Iron Studios (THQ) as a gameplay programmer on several licensed games.

How did you develop the idea to present a shoot'em-up in reverse?

MG: When we started 24 Caret Games, we wanted to put together a demo in order to get interest from publishers in our company. We were working on something that we’d like to make into a full game, but after almost two months of development, it seemed like the budget required to make it would be too high for it to be successful as a downloadable title in the current marketplace.

Right now, it seems like few indie downloadable titles sell over [100,000 copies], which means that if you want to stay in business, you have to have a very conservative budget. It was a tough decision, but we decided to go back to the drawing board and work on something that stood a better chance of keeping the company afloat.

On our initial demo, we implemented a debugging mode for backing up time in order to repeat sections and fine tune gameplay. My co-worker, Justin Wilder, had the idea that it’d be really cool if we could actually play our game in reverse. I couldn’t think of a way [for that] to work with the gameplay we had, but when we decided to start over, I thought about how to make a game that could be played in reverse.

The idea of repeating predetermined actions is a bit tough to make interesting. I thought the best way would be to constrain the movement of the player character as much as possible because trying to match an arbitrary position in space would be very difficult. As well, I saw that this would make a great rhythm game since we’d need a good indication of timing.

Making it a reverse shoot’em up met all the constraints. As well, in many rhythm games, the visuals are pretty dull, so we thought making the reverse space battle would be cool for any onlookers as well as the players.

In the more difficult modes, you increase the number of space lanes and enemy fire. Did your team explore any other changes to provide more challenging levels to advanced players?

MG: We’ve been very fortunate to get many volunteers from friends and family who are at all different skill levels to focus test in order to help balance the game. One of the main design goals is to make the game accessible and enjoyable to everyone regardless of skill level.

There are a few rules right now that I’ve developed for each difficulty level. They are a work in progress, but currently the rules are as follows. For easy, all the lasers fall on quarter notes, and the patterns are all very simple and repeat often in order for the player to get the hang of them.

For medium, the patterns are more complicated and have less repetition, and there can be lasers on the offbeat, but no eighth notes together. For hard, there are eighth notes together, but always in the same space lane. The hard patterns have little repetition.

For expert, we have eighth notes in different space lanes and some tricky patterns involving the player needing to change lanes rapidly. I’d like to add another difficulty, but I haven’t quite decided where it should go in terms of the difficulties we already have to create an experience that everyone can enjoy.

For a shoot'em up, Retro/Grade's music is, at least in its gameplay trailers, a lot more subdued than the songs you'd find in other titles in the genre, like say Gradius. Could you share how your team came up with the game's sound?

MG: It was difficult to come up with a style that we felt would work well as a rhythm game. Since this is an indie title, we don’t have the resources to license music from [insert your favorite artist here]. However, since this is a rhythm game, we needed to make the music stand out and be something that gamers would enjoy.

We thought it would be cool to do a chiptune/8-bit influenced soundtrack because it matched the retro feel that we are going for and would be appealing to gamers. However, we wanted to take advantage of the high quality sound hardware and not alienate younger audiences that missed out on the 8-bit generation, so we didn’t want something that is pure chiptunes.

We were fortunate enough to be able to contract Skyler McGlothlin, one of my personal favorite musicians, to do the original music and sound effects. It’s very difficult to describe to someone what you want music to sound like, but we did our best to give him an idea of what we were looking for, and he really blew us away with the songs he delivered. I often find myself listening to the MP3s of our soundtrack.

What other music styles did you experiment with?

MG: For the demo we submitted to the IGF, we didn’t have time to create original compositions, but before we contracted Skyler, he was nice enough to give us permission to use tracks from his first album called “Are You an Axolotl” (released as Nautilis).

The style is a bit hard to communicate because it’s quite unique, but I think it would be best described as IDM or glitch. Unfortunately, the intricate drum rhythms made it difficult for the less rhythmically inclined players to place the beat. We decided that to reach the largest audience, we’d need to carefully compose songs that would be easy to follow the beat.

Why did you decide on a horizontal-scrolling shooter, instead of a vertical-scroller? Wouldn't it have more resembled the familiar layouts of music games like Guitar Hero or Rock Band?

MG: Most new displays for both both PC monitors and TVs are widescreen, so we wanted to take advantage of the additional screen real estate. Scrolling the gameplay horizontally on a widescreen display gives us almost twice the space. The extra space allows us to have bigger and better implosions, [and makes] the timing information easier to discern from the positions of the lasers.

You have a normal control scheme for game controllers and keyboards, but you also have a rhythm game control scheme for guitar controllers? Could you talk about how the game play differs with the two control schemes?

MG: I’m a huge sucker for peripherals. I have about every ridiculous peripheral made including the Onimusha Katana Blade Controller, Steel Battalion’s massive simulated cockpit, and The Maestromusic’s conducting baton. The only problem is that often these cool peripherals only work for one game. Although our gameplay differs from guitar-based games, I thought it’d be fun to give people the option to use their peripherals on a different title.

The two control schemes we support are a shooter mode and a rhythm mode. The shooter mode is simpler because you just move the ship up and down and there are buttons to fire and to use your power ups.

The rhythm mode allows you to jump to one of the five space lanes based on which button you press. The rhythm mode is supported on gamepads as well as the keyboard, but since there are five fret buttons, it is a good fit for the guitar controller.

The game is designed so there isn’t an advantage of one control scheme to another -- it just comes down to personal preference. Since in shooter mode, the ship can only move up and down one lane at a time, there’s a limit to how fast the player can move between several space lanes.

However, which space lane the player needs to be in doesn’t have too much of an effect on the difficulty when using the rhythm mode scheme, so allowing the gamers that play with the shooter scheme time to go between lanes doesn’t make the game any less enjoyable for people playing with the rhythm mode control scheme.

Were there any other elements from shoot'em ups, rhythm titles, or any other games that you tried to include, but decided that they got in the way of Retro/Grade's accessibility?

MG: I’ve played percussion since elementary school, so I wanted to support drum peripherals somehow. I tried mapping the controls in several different ways to different drum peripherals, but it didn’t pan out. I’d rather not support drum controllers if it’s not going to be enjoyable.

Were there any elements that you experimented with that just flat out didn't work with your vision?

MG: I tried to make the premise more detailed with a bunch of silly jokes, but putting a bunch of text at the beginning really made it slow for people who just want get to the game.

I’ve done two or three passes on the epilogue (the training mission for a game in reverse) to pare it down to the bare minimum to get people up to speed on the mechanics. I realized that people playing a demo just want to get to the gameplay and see if they enjoy it.

Going forward, perhaps I’ll be able to work more humor in between levels, or at the very least, provide some supplementary materials on the web for people who really dig our game.

What sort of development tools did your team use?

MG: We use Maya for 3d modeling and Visual Studio for coding.

If you could start the project over again, what would you do differently?

Ideally, we would have started on Retro/Grade as soon as we formed the company. However, that would have been difficult since the core idea came from something we thought of while working on our initial idea. We also spent some time early on looking at doing projects for other people, but we didn’t find anything that was a good fit for our strengths as a team.

What do you think of the state of independent game development, and are there any other independent games out that you currently admire?

MG: I think due to the rising costs of development for the average game, independent games are emerging as the main source of innovation in the industry.

Last generation when there was more titles being developed (all with significantly smaller budgets), publishers were willing to have a few risky titles in their portfolios on the chance that one would become a smash hit. From an economic standpoint, it doesn’t make sense for a large publisher to gamble $10-20 million dollars on something that is experimental.

However, passionate individuals are more than willing to bet on their ideas because they believe in them. This is the independent spirit that drives people to create some really amazing games that push the envelope of games as an artistic medium.

In particular, I admire the work of Jason Rohrer. He created Passage, which despite running at a resolution of 100x16, manages to create more real emotion than many of the big budget games with the most realistic graphics. I haven’t found someone to play Between with yet, but I’m excited to play it and will be rooting for him at the IGF.

One thing about indie games that I find pretty unfortunate is there is no publisher that focuses on funding innovative, low budget projects. The problem with self-funding projects is that if a studio’s first indie title flops, they may not be able to afford to create another title.

There are many reasons why an indie title can flop that aren’t a reflection on the skill of the developers. Perhaps a similar product came out at the same time and stole some of the spotlight away. Maybe word of mouth didn’t travel fast enough to keep the developer afloat. Or perhaps the harsh economic climate caused the developers to run out of money before the game was completed.

I would think that it could be quite profitable for a publisher to fund innovative, low budget XBLA/PSN/PC downloadable titles and take some of the risks away from the game developers.

Obviously, the small developers would be trading risk for a share of the profits because the publisher would have to amortize the games that weren’t profitable with the proceeds from the games that were. Maybe that would take some of the indie spirit away, but it seems like a business model that could be mutually beneficial to all involved.

As well, it could help push the medium forward by helping new ideas turn into fully-realized games that wouldn’t otherwise see the light of day.

I imagine that no major publisher would be interested in having a division that focuses on indie games because they would much prefer to devote their resources to their large financial risks, so they don’t have the bandwidth to put people on these smaller projects that could be profitable, but are a small fraction of the company’s revenue.

Perhaps one of the smaller publishers will move into this market and provide developers with financing, QA, localization, a small amount of marketing and put their games on all the popular digital distribution channels.