Hey there.
I've gotten to the point where i can start to code something for my cannon game now. I've put a fair amount of work into concept drawings and the game flow and game play. I'm working away on an upgrade system, whereby you get points for killing certain enemies, the closer they are to you, thus more dangerous, therefore, the more points you get.
Also, each enemy has weakpoints, if you shoot, you get more points and the enemy dies quickier.
Now, the cannon has 4 upgradable sections:
The Barrel - Reduced friction barrels, reduce overheat and increase shot strength (power)
The Weapons Module - This rotatable section holds various weapons, which rotate in line with the barrel and shoot.
Power Module - Determines the shot strength (varies from weapon to weapon) and the rate of fire.
Coolant Module - Determines how long the cannon can fire for, before it overheats, and shuts down briefly.
Further more, each weapon module can be upgraded. I'll give one example:
Landmine Mine - A mine that is shot from the cannon and sticks to the first thing it touches.
Upgrades:
Explosion: levels 1 - 4
Blast Radius: levels 1 - 4
Detection Radius: levels 1 - 4
These can all be upgraded. Now the question! Do you think this is too much stuff to be upgraded in a game? The game will probably have about 20 levels max. Each level consists of waves of enemies coming towards the cannon, and you have to kill them. The cannon will be static most levels, occasionally travelling, but the idea is the same.
I know this might not make much sense, so sorry if i haven't explained it too well. Here's a photo of the upgrade sheet drawing.

EDIT - Thanks Ginger Tea.
I've gotten to the point where i can start to code something for my cannon game now. I've put a fair amount of work into concept drawings and the game flow and game play. I'm working away on an upgrade system, whereby you get points for killing certain enemies, the closer they are to you, thus more dangerous, therefore, the more points you get.
Also, each enemy has weakpoints, if you shoot, you get more points and the enemy dies quickier.
Now, the cannon has 4 upgradable sections:
The Barrel - Reduced friction barrels, reduce overheat and increase shot strength (power)
Default - Barrel with low anti friction properties. Upgrades - Lower friction - Even lower friction - Ultra low friction (They will have better names in the game!)
The Weapons Module - This rotatable section holds various weapons, which rotate in line with the barrel and shoot.
Default - 2 slots for weapons Upgrades - 4 slots for weapons - 6 slots for weapons
Power Module - Determines the shot strength (varies from weapon to weapon) and the rate of fire.
Default - Standard power cell Upgrades - Dual power cell - Quad power cell
Coolant Module - Determines how long the cannon can fire for, before it overheats, and shuts down briefly.
Default - Water coolant default Upgrades - Alcohol coolant - Liquid Nitrogen coolant (more research for names required!)
Further more, each weapon module can be upgraded. I'll give one example:
Landmine Mine - A mine that is shot from the cannon and sticks to the first thing it touches.
Upgrades:
Explosion: levels 1 - 4
Blast Radius: levels 1 - 4
Detection Radius: levels 1 - 4
These can all be upgraded. Now the question! Do you think this is too much stuff to be upgraded in a game? The game will probably have about 20 levels max. Each level consists of waves of enemies coming towards the cannon, and you have to kill them. The cannon will be static most levels, occasionally travelling, but the idea is the same.
I know this might not make much sense, so sorry if i haven't explained it too well. Here's a photo of the upgrade sheet drawing.

EDIT - Thanks Ginger Tea.