I'm very frustrated with the latest update. I've been saving 500,000 coin for upgrades and special events. With the latest purchase slider for cards defaulting to max I just bought 500 cards and flooded my inventory. It didn't cap it at my max storage either.
My ultimate deck... 8 Peasants, 2 Parting Gifts, 3 Portal Growth (I don't have more to add), 15 gold generating cards and 5 mana generating cards. I win in 3-4 minutes. This deck is really effective on the high levels because the computer kills your peasants faster.
My method for beating the game on hard:
1. sell the fighter bay (only 8 credits back but it forces all enemy ships to fly straight for you so you can target them very easily)
2. upgrade the ultragun's damage and fire rate. Don't bother with health or speed, you need the credits for repair. Remember that 'Z' is autofire.
3. Repair upgrades. Get them all but not too soon. Concentrate on the ultragun first.
3. Build rocket turrets. Do NOT build on the front 2 spots as they get blown up quickly. The 2 bottom spots tend to be soft also. Save all those softer spots for much later.
4. Win.
I also completed level 78 when I was 61 but traps were critical. Mana Gain, Bouncing Mastery and Dual maxed. Gem bomb orange and lime them into your inventory. Trap orange lvl3. tower combo lime/orange. Unlimited Mana but a lot of micromanagement.
A fun concept and nice execution. There is a small bug with the boss. When you are close to the bottom edge (right button) there can be a space between the paddle and wall.
Hero character is an excellent idea. Multiple tower choices and changing ability of towers keep the strategies interesting. Adding roads, gates and shortcuts helps keep interest in the game. Only problem is a road, shortcut or gate destroying already placed/upgraded towers.