Play online.

Seriously, its as easy as that.

Hard = 1.5x gold and exp...for everything. Not just creep waves.

Nightmare is 2x.

The key to beating them is xp, xp, xp. Get the xp bauble, and guard the xp flag like no tommorrow. If you have the flag, park yourself at the nearest creep lane and farm. Of course, make sure to make visits to the item/artifact/citadel shops.

Next, the normal AIs you have are going to do nothing but feed the nightmares. They do not have the advantages as a player you do, so they are guaranteed to fall behind the nightmares, and as such will just give them lots of freep xp/gold. Hard should be able to remain competetive enough.

Against Hard AIs I've found that having either increased run speed or Poisoned Dagger for snare effect early game can make a big difference. The main problem I've found against Hard AIs is that I can almost kill the AI but then they run away.

However, this tactic is not as effective against players so don't expect your tactics for defeating hard AIs to all transfer to online play.

thanks to all those above who gave me tips and hints .

this is what that went wrong.

i'm lv 20, my teammates are all lv 15. they're all lv 20. there was once i fought against 3 rooks and a sedna and an oak. my team pushed them back to their base (they're were all at equal levels and i was level 20) however, suddenly they managed to push me back and my team. i tried to kill a rook but he took off at ninja speed. it's probably journeyman treads but anyway, i couldn't kill any of them because 1) they had a very high health regen and/or 2) they had very good life steal. i wasn't using any made up on the spot build. the builds i used are ooze ub, assassin oak (no ward) etc. i can easily take on a hard mode dg. it's when they stack on me which makes it extermely hard . and my team of normal AI (4 of them) can still be pushed back by a sedna and a rook . -.- i bought every single creep upgrade and spent most of my money on the citidel upgrades and because i killed alot, i had money for artifacts. i probably had more than 200+ hp regen with -25% damage from bulwark of ages etc. but when 3 super fast rooks come pummeling down on you, you can't run ..

to rawrrrrrrrrr,

1) i didn't run back to base much. i only went back when i had enough money to buy a few upgrades and armours / weapons .

2) i focused on the flag nearest to me and not the xp flag . that's probably why i lost.

3)i don't use potions lol .

4) theres still a limit to how much you can stack . in all my games, i stacked them to 7-9k + however, the enemy dgs also have the same amount -.-

5) i seldom bring teleport scrolls so thats probably where i went wrong as well.

6) like mentioned earlier, i don't use some make up on the spot build.

7) this is how i buy upgrades, currency, the first upgrade for the hp regen on towers and damage on minions. and after this, my main focus are stronger creeps.

well here's a few thing i would do next time, play online (yes i admit i never play online >.>), use caplocks and bring teleports around.

however, i'm still open to more advice so yeah .. keep them coming

also, i couldn't find any basic tutorial on dg e.g. what to focus on and what not therefore i didn't know what was important. i'll try another game later when i get back from school and i'll see if i can win this one.

is it not important to kill ? do assassins take buildings as well ? 

edit: i tried again but i lost . these normal AIs in my team just feed themselves to the hard AIs on their team. i focused on caplocking, keeping exp flag, killing minions. i got to lv13 while the enemy was at lv 10-11. my team was at lv 5-7 -.- i even focused on getting creep upgrades by selling my items. 

This is so easy I haven't played AI lately but this will be a cake walk will post replay tonight. Who do you want me to play as?

The AI is dumb and will always walk in range of towers. Your best bet is to kill them as early as possible by kiting them into towers. Infact, this is one way to make sure your build has sufficient crunch power, as the AI will walk away once it hits about 25% health. If you can kill them without them walking off, you are on the right track with your build.

Do not let them kill your teammates, the consequencves are dire since they get gold and XP bonus. Buy priests as your first upgrade ASAP (the healing is really useful to keep teammates alive). Also note that this is not usually a good idea on real games against humans.

Nightmare AIs also seem to get free gold at the start of the game for items... as I see things like Theurigst hat effect on myself at level 1 during the 1st encounter.

Still doesnt help them, the AI is dumb.

http://www.gamereplays.org/demigod/replays.php?game=51&tab=upcoming&show=details&id=103182

The site seems to be down for me. The only thing I can think of that might be causing a problem are the mods enabled during the match. Nothing game changing, except a fix for TB's AA and Peppe's mod that actually makes the AI smarter. I don't think that should be causing a problem though.

post it here so everyone can see it ?  

if you dont have allies they can't feed, so its actually easier to win w/o AI allies

I would also say that health stacking against the AI is not that important as against human players. It is more important to make kills, so you need more damage. Try only to be on pair with the AI with the HP but outdamage them. So for many/most demigods I upgrade Mana much more than HP.

The method I will state now works with every demigod. I have played it like that with all demigods and won the games. When I play against the AI I usually buy Scaled Helm and Banded Armor at start. At the first trip to the shop I buy a teleport scroll and a Combat Health Potion. That potions are very important, as it allows for kills to hunt the enemy even if you are low at HP. Try not to waste them, only use them when you are going to die otherwise. In contrary to play against humans it is not that important that you do not die. Your AI team will feed the enemy anyway sooner or later. So if you see a good chance for a kill but you see also you will also die then take the kill. You will get gold that you can use for better items. So when I have the gold I usuall buy as first item afterwoods a Vlemish Faceguard. This will produce a nice amount of mana so you can cast more of your spells. Try to kill creeps whenever possible as the AI should not outlevel you too much. The next item I often buy is Unbreakable Boots. This will boost your HP and your mana. That is what you need to stay in touch with the AI. Then Theurgist's Cap is quite good, as it gives a boost in regeneration and mana. Later in the game when you have enough gold you can replace Scaled Helm with Hungarling's Crown which should solve all mana issues. Before you buy more mana stuff it is usually needed to buy a health item. If you get into troubles early then Nimoth Chest Armor is cheap and will do the job. If you have no problems (should usually be the case) you can go directly to Narmoth's Ring which will help a lot. If you have still no problems when you have 4000 gold and make frequent kills then try to go for some artefact instead! Sometimes I have skipped all items after Vlemish Faceguard. This is especially then possible when Rook is at the enemy team. Rook AI is slow and dumb so an easy target to kill. If you have an enemy Rook this is your primary target. Not only he is easy to kill but if you kill him frequently he will also fall back level wise (compared to the other AIs), so he even get easier to kill. If no rook is available then watch out for AIs with low HP like Torch Bearer. You search easy kills. Avoid especially Sedna. Their healing skill is annoying and you want to get easy kills. In addition it is also important how you fight against AI. Attack the AI and try that they follow you to your towers. They will run into it. Wait with your skills (if the do not reload quickly) until the HP of them is low and they start to flee and then finish them off. Here are the health potions important. It is ok to spend 275 gold for a kill. The same ist true with the 500 gold for a Sigil of Vitality later in the game. In addition always have at least one teleport scroll so when you see an enemy with low healt points you can teleport to him and kill him. For the citatdel at the beginning of the game you only need two upgrades. The first is the upgrade so the towers regenerate and get more HP. This update is very important so I often buy it even before the Vlemish. You need your towers to hide and help you to make kills. The AI will attack the towers, so you can wait there and attack them from there. The second update is the gold upgrade. This gold increase is very good. So buy it quickly. This will also help your AI team not to die so much.

I hope that can help a bit. I had a replay somewhere where I made 220 favor points in a single game in Nightmare tournament with that strategy but that was 1.19 so it will probably no longer work. Will try to make a new one with 1.20.

To show how you can beat the nightmare AI I have made a game in the tournament.

http://www.gamereplays.org/demigod/replays.php?game=51&tab=upcoming&show=details&id=103334

Here I played with the Unclean Beast which is IMO the easiest Demigod to dominate the AI. As you can see it is not only possible to win against the AI but dominate it (I made 35 kills while all enemy AI together made 13 kills). At the end of the game I was level 20 while the Nightmare AI were still level 14 to 18. Actually I tried to make all 220 favor points but died some silly death so it was impossible.

You will see in the replay that through making many kills I got much gold for good equipment while the nightmare AI could not level that fast as it was often dead. You will also see that against the AI (at least if you play that play style I do) HP are not that important but Mana is very critical even for the Unclean Beast. As I took Staff of Renewal as favor item I was able to spam Spit and Fould Grasp. Together with Ooze this is deadly but it cost a lot of mana.

Actually it is possible to win with all Demigods against the AI. It is not as easy like with UB for all of them but a solid win is possible with all. I you want I could provide also some replays with other Demigods.

btw. when you watch the replay you will see that all Demigods at Nightmare have a Narmoth's Ring (also Rook) as start item. The point with artefacts is true. It is bad when the AI get them before you but it is still possible to win sometimes (depending on the map). You have to focus on the goal like destroy the citadel and ignore the rest.