and another game ended prematurely at turn 197. it's pointless to play the game until they either fix the unity winning condition or give us the ability to disable certain victory conditions. i consider this game breaking and it needs to be addressed asap.
there is quite a lot of things being wrong with the unity spell. simply put, 5000 mana isn't enough by a large margin.
a) neutral monsters are pretty strong on impossible and greater fire elementals are a real show stopper. that leads to the AI (or players, once MP hits) being too isolated and too protected from attacks. build three cities, mana farm them up, press enter 200 times, win the game.
b) a much bigger problem is that at 5000 mana, unity doesn't fit into the flow of the game. units cost so much, both in initial investment and upkeep that 5000 mana pale in comparision.
at the current costs, early midgame happens around turn 150. at that point you'll have 4-7 cities, depending on environment and the first small skirmishes will be waged. the game ends at turn 200. doesn't work.
everything below tier 2 units is utter crap. tier 1 dies to everything, even spamming them is not an option. tier 2 is barely manageable, but depends heavily on the units available. f.e. you can get quite far with vampires, but some other t2 choices are just as crap as tier 1. now consider that tier 2 already costs around 100-300 gold per unit. that is a lot. to even maintain 4 vampires (equivalent of an elder vampire @ 800 g) you need 5 cities, full with banks, farms and mana traps. it is impossible on impossible to invest into more than 1 or 2 different kinds units, because if you do, you'll be crippling yourself by having all that shiny tech occupying your space for food/tech/mana. i don't disagree that it should be hard getting units out on impossible and that you have to really think how to build up your cities - that is great - but if you do that, ending the game at turn 200 is simply not feasable.
ideally, you want to have tier 3 units. those cost around 1000 gold and require a lot of upkeep. you will need around 10 cities fully saturated with mints, mana farms and farms to support more than just a single one of those units. please note, that you'll hardly manage to even get one of these units out before turn 200 unless you had some insanely good starting location.
since unity happens around midgame, we don't need just a slight increase in cost. i estimate that around 100k mana would be the neccessary requirement on unity to bring the game into lategame. some people will certainly scream "but raw, that's totally overboard" and yes it is. just to do some math: with 5k mana requirement we now get to turn 200. assuming there is a linear progression 100k mana req. on unity would bring us to turn 4000. however, as I understand how these games work, the actual increase in mana over time is exponential, since over time more players get weeded out and cities get build and conquered so there is more mana per turn per user.
here is a little math. we know that after approx. 200 turns we reach 5000 mana. assuming a constant rate of flow, that means about 25 mana/turn. i think it's pretty obvious that we never see such a high number happening on the ressource bar. that means that both the trickle in-effects (by quests, loot, etc) and the exponential growth due to our expansion is significant.
if we assume exponential growth, we have to do some math first:
m(t) = exp(c*t)
dm/dt = c*exp(c*t)
m(t_f) = m_f = 5000
t_f = 200
c = ln(m_f)/t_f = ln(5000)/200 ~ 0.04
assuming we want the game to last 500 turns on average[*] before unity becomes generally available
=> m_f = exp(0.04*500) ~ 500 million mana
if we keep the linear ansatz:
=> m_f = 25*500 = 12.5k mana
the real behavior is somewhere between linear and exponential, so 100k seems like a good choice.
does that number sound ridiculous to you? that's because it is. mana is too readily available in the game, while gold is extremely scarce. you have trouble sustaining an army of more than 3 units, but can win the game via unity with 3+ cities no problem. we arrive at the inevitable conclusion that unity, in the current frame of the game, is completely broken.
tl;dr: build mana farms, ignore units, win the game
[*]remember, early midgame happens around turn 150.