Additionally to most stuff from our coders' concept paper we talked about the following stuff:

Rules of gameplay
We need a enduring motivational system. Possible approaches for that problem would be different game modi like Genocide (kill all birds in the level), body count (kill as many birds in a fixed time as possible), Anti-Conquest (keep a number of areas clean of birds, when no bird is in your areas a countdown continues, get it to 0, it somehow can increase again). All of those could also be done competitive or coop(^1)
Additionally JP came up with some kind of a achievement-system which gives you credit when you do special things like killing 5 birds in 3 seconds, killing 50 pigeons on the same laser fence or such. You could use this credit to either unlock new equipment or improve already achieved equipment.

When you finish a level you get lifted up (e.g. by a hot air balloon) to the next level of clouds = next level. When you fall/jump off the cloud you get set back by 1 lvl (made easier to limit frustration?). That way you can go back and collect credits for better equipment if a level is too hard.

There could be a "boss pidgeon" or such fighting back at you. It would do no damage, but hinder you on hunting the birds and maybe poke you around.

For the sticks: Should the player place them before the level starts or while it is running and might he/she pick them up again?

gamedesign & graphics
Sticks
We could have several (3-4, max 5) types of sticks with their very individual skills, properties and abilities. They should be build in tileable sub parts which then could build up structures as high as it gets, the top being a single part on the tip - works only for "cylinder like" sticks. "Conne like" sticks should be rather skaled. But even there you could have a seperated tip that then does not scale with the stick.

Weapons
A child should not bear "weapons" at all! So our ill-minded inferior uses tools and stuff from the household instead. E.g. a broom, pan, golf club, lamp, wooden spoon, ice-hockey club or such. Or his all-time-favourite ultimate weapon of bird destruction: The oversized lollypop! Oh and his feet of course.
Anyways all those weapons don't kill the birds. It only "repostions" them to a place the player would like them more to be - for example inside a laser fence. If a bird is kicked off stage it will fly back in.

Items
As of now we only have one single item. A pouch of bird's seeds to feed and attract the birds. This maybe useful to lure them near a deadly fence and "sweep" or shoo them all into it.

The Child (finally)
up to now we got a boy of round about 6-8 years of age, wearing a T-Shirt and shorts together with boots. We should show everything on him, he bears so far (the pouch of seeds, all his weapons). Therefore we maybe should restrict the number of Items you can use at a time. Maybe at max one 2handed and two 1handed weapons + 1 item. The rest should either stay in the balloon or be stored somewhere in the level. You keep all your stuff in store even if you get new equipment.
The movement is very clumsy and simple. Also he can bend his arms&legs but he has no visible knee or elbow. Up to now we don't know how to texture it considering cartoon/cell shading appearently works best with single coloured polygons. But that would dramatically increase our polycount on the equipment and the boys head.
Does he need a name?

The imaginary friend
We haven't talked about him, but we should point down his nature soon. I would like him to appear at least in cutscenes and definately as a voice-over. If we show him I would like a natural enemy of pigeons like a fox as his visual. Somewhat twisted as American McGee's Alice visualised the Cheshire Cat.

Birds
Have we agreed on pigeons now or will it be more like the twitter bird? We should get that down soon. After that we could agree on a visual for those.

^1
Split screen or network? Split screen would cause us to ignore the mouse as a control instrument, network would need some kind of network code...