What worked for me was metropolis & nature, start with Hitman and convert to Mr. Iron or Electric Chair in the endgame. If you get Ganesha, turn it into Stonecutter's Temple as soon as it reached level 99. Another reliable strategy at the moment seams to be to build a lot of Wolves. I tried to beat hard with that strategy last weekend, but I miserably failed though ^^.
My early game is nature only and solara. As soon as the solars is strong enough and I have at least 6 wolves she will be converted to a wolf. Get wolves out as much as possible. Ganesha and manitou are important to increase their strength. This can get you to bonus round. When you get some good items and knux.
I have similar strat as kami, but instead of solara i use more rabbits and turn every single tiles into wolf. Finished my first 500s using lycaon, maybe that'll help. I'm quite curious of everyone's endgame strats though...
The game is definitely harder than it used to be. I find that without good item drops before level 50, I have a hard time between 70 and 120 or whenever I start to get good items (plasma blade, Excalibur, etc.). Wolves are a good strategy and probably the most reliable one. With wolves, you can get every tower to level ~30 without much difficulty. Wolves can last you until around round 200. After that you need to transition to a stronger tower. Be careful with the transition, because your wolf tower will have a huge wolf pack buff and any simple tower swap out is unlikely to work. Using Yggdrasil with the wedding rings gets you double potion effects for your carry tower. That can help a lot. With Yggdrasil, you can give a nature tower some good potions to get them going, then switch them to Ripper to start stacking thirsts (only viable with very low attack delay (Below 0.1 and as close to 0.01 as possible). I think Andy said he isn't planning any major changes until the Light deck is released. Hopefully that will come with some buffs to ease the difficulty of the game.
I have to say i like the difficulty. I personally think Ripper is a Bad Carry a well placed abyss king and potions will make his passive useless.
Thanks for all your replies! I've managed 900 secs bonus round with wolves on easy now. Lately I've been trying to save as many pots I can and replace my alpha wolf with yggdrasil, with all 5 branches on itself, drink all the pots and then place another wolf. It's given me some pretty good times. However... I still play on easy like a noob