Needs more upgrades

Please allow more upgrades to the cannons and health for the tower in the upgrades and possibly the characters to.im stuck at a higher level Ive got all the upgrades except the last special weapon and I cant win even though I am a pretty good player.why not let us keep upgrading until we can win because some people might not have the skill to finish the game without them

Scifistephen about The Long Siege