I don't understand why they changed the price of bonus content form the first kingdom rush. 60 kreds in the 1st kingdom rush unlocked you all the bonus content and now in frontiers, it cost 10, 30, or 50 kreds for only one hero. Other than this little gripe, the game is fantastic.
You should add a pvp arena where people can buy stuff for their penguin like swords and bows and fight each other for exp, cash, and cool rewards. press plus so the developer can see.
HOW TO GET THE BEST STATS:
1. Get far enough into the game so that you have the level 4 upgrades unlocked.
2. Achieve a starting cash of 2,000$ +
3. Now that you have these, the first upgrade you should buy is the level 4 flag (not the speed one ). Then upgrade your ship and save up for the level 3 flag. Again upgrade your ship and buy the level 2 flag.
4. Ok now save up and upgrade your ship again and buy the level 1 flag.
5. Once you have enough money for the level 4 cannon, sell your level 1 flag and purchase the level 4 cannon. (You now have max weapon ) This setup will help you defeat the final boss easily.
6. If you want to get really far then upgrade your ship to the max and buy the level 1 flag again.
7. You should now have all the flags purchased and max weapon. :)