rose knoll
The base idea that came to mind was a combination magic/mana.
Main gimic of them would be that its towers need mana to function strongly, and mana held as an additional resource and created by the utility tower.
Each spell would have its own cooldown, maybe a small thing above the tower for its spells (could just be a 2 pips for T-2 upgrade spell, 3 for T-3 and its colour based on the spell you upgraded).
Some spells would also be active spells that cannot be cast unless the player interacts.
Its worth noting my original idea would be that when you upgrade towers, they don't loose access to spells previously upgraded into. However that idea could be changed depending on the vision of the game.
4 towers: 1 eco (always) 2 damaging and 1 utility tower
Starting in a specific order:
The utility tower would be a bowl (like the top of a bird water pedestal) that would collect mana over time, the tower would have a range that increases on upgrade. Its upgrades would be based on how it gains mana, capacity and bonus effects.
Examples: T-2 upgrades of gain more mana when a nearby ore is mined, gain flat mana on enemy death, gain mana on proximity to enemy basin.
T-4 for every 10 mana gained by this tower, give a nearby tower a free 'cast'.
First offensive tower could be a small rock/magic themed tower that as it upgrades gains a rune type feel, glowly lines etc. The tower would start with a slow arcane blast it fires (give it a tiny aoe with a limit of hitting only like 3 units), all of its upgrades would give 'spells' that consume mana to have powerful effects, thinking fireball, ice lance. Steriotype spells. Some upgrades could buff its basic attack, but overall its based around offensive spells.
T-2 could give a frost lance, firebolt or a magic missile, T-3 could be more powerful ones like rock throw, waterstream, T-4 iconic spells like fireball, earthquake (aoe).
Second offensive tower could be a kind of 'magic conduit'. Its first effect would be to cast an aoe that hits the ground and leaves a persistant slow (low damage). This would be the main way of stopping enemies from reaching the basin as no walls. Its upgrades focused around debuff spells like poison, enemies taking more damage, T-2 could be a roots spell that gives a small stun on enemies in it/walking into it. T-3 could be a small ice wall that has like 50 hp? T-4 could be to teleport group of enemies back to their basin.
Finally the eco tower is harder to say its looks, somebody gave me an idea of a magic tree which I think is good. But the idea of using mana to cast utility spells that buff mining seems cool. Alongside a few ways of gaining mana from T-3 or T-4 onwards.
Potential for some cool T-4 and T-5 using mana, obviously discussion welcome!!
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