How can you judge what is a "reasonable amount of time" to be working on a game?

[Cereal Guy]

You don't. Just work on your novel in iterations, and you'll finish it.

[Saitoki1582]

Many people here already mentioned the main point : plot outline is very very important in team work. The first thing I consider after creating a nice premise is "How will it end?". If there's multiple endings then " What is the best and worst way it can end?". Then I would go up from there to add plot points and characters role in it. don't just discuss small ideas about details before having a concrete foundation you can build those idea upon. When there's only one writer, they might just be able write thing to the end without an outline because they already have a vague idea of how to end it. A group of writer however can't look into each other head.

Once you have the outline, you can already decide what art asset needed without the full thing written. Location ( BG), characters (sprite), important points in story ( CG). Try to scope down the art as much as possible, if a location only appear once with a few passing lines in the story then it might not need a BG, use a black screen instead. Focus on Sprite and what you consider the most important scene for CG, only add more if artist finish with them first.

As for your main question, it's depend on how much you and your team are willing to cut down on the scope. If you are willing to get it down two 20-30k words, a cast of 4-5 important characters with sprites ( and extras without sprites), 5-6 locations and 5-6 CG , 3-4 month is not implausible even taking in break time ( because art block/ writer block). If it's your group's first project, then it's advisable to start small, because a close, attainable deadline help a lot in driving up motivation.

[XBDC36]

Many people here already mentioned the main point : plot outline is very very important in team work. The first thing I consider after creating a nice premise is "How will it end?". If there's multiple endings then " What is the best and worst way it can end?". Then I would go up from there to add plot points and characters role in it. don't just discuss small ideas about details before having a concrete foundation you can build those idea upon. When there's only one writer, they might just be able write thing to the end without an outline because they already have a vague idea of how to end it. A group of writer however can't look into each other head.

Once you have the outline, you can already decide what art asset needed without the full thing written. Location ( BG), characters (sprite), important points in story ( CG). Try to scope down the art as much as possible, if a location only appear once with a few passing lines in the story then it might not need a BG, use a black screen instead. Focus on Sprite and what you consider the most important scene for CG, only add more if artist finish with them first.

As for your main question, it's depend on how much you and your team are willing to cut down on the scope. If you are willing to get it down two 20-30k words, a cast of 4-5 important characters with sprites ( and extras without sprites), 5-6 locations and 5-6 CG , 3-4 month is not implausible even taking in break time ( because art block/ writer block). If it's your group's first project, then it's advisable to start small, because a close, attainable deadline help a lot in driving up motivation.

Sorry for responding so late, I didn't think any more people would still be responding to this thread, but thanks a lot! Yours by far is the most concise and touches on a lot of the things I was struggling to put into perspective since I'm working with another writer now like how the story should be handled and how that melds together with what type of art is required! I appreciate your response very much!