Wouldn't it be cool if there was head-to-head Kingdom Rush where one person is the towers and the other is the enemies? Here are my ideas.
1: Random matchup and private battle (via code or steam friends list) modes.
2: Before you match up, you get to choose from Lineria, Stormchill mountains, Valardul, Haunted Valardul, and the Burning Torment stages.
3: Once you match up, a map from the zone you chose will be chosen at random.
4: Sides will be given randomly, so you'll have to have experience with both.
5: While the towers side prepares their defense, the enemies side chooses 10 types of enemies, each with their own balanced price. Enemies native to the zone are discounted. Neither side can see what the other is choosing.
6:The enemies also choose 2 of these powers (Bold powers are situational and are only present on certain stages):
Conscription: All enemies cost 2/3 of the price for 3 seconds.
Ves'nan's Curse: 3 random towers are disabled for 5 seconds.
Graveyard/Skeleton Grave: spawns 10 skeletons from a graveyard/skeleton grave of your choice.
Summon Magma Elemental: Summons 1 Magma elemental from the elemental spawn point. takes quite a while to recharge.
Thermal Vent: activates 1 thermal vent, burning soldiers for 5 seconds.
Poison Pool: activates 1 poison pool, reanimating fallen soldiers and elementals as husks and swamp things, respectively for 10 seconds.
Zombie grave: spawns 10 zombies from a zombie grave of your choice.
Reinforcements and rain of fire work as normal.
7: The towers side and enemies side get a balanced amount of gold for the map. The towers get gold normally, the enemies get periodic bursts of gold, and extra for every soldier or elemental killed.
8: The towers goal to survive 15 waves of enemies. The enemies' goal is to leak 20 lives before the towers survive 15 waves.
9: Bosses are not present, but neither are heroes.
10: frontiers could be added in a future update, but Ironhide will have enough on their hands doing this for original for quite a while..
That's all! Feel free to give feedback and suggestions!