The best part of spore but that's the whole game

<chef's kiss>

Probably one of the most creative Roguelikes ever created, because every Sipho you make is saved in the enemy library, the game uses all of your failed attempts to defeat you, as in as you get better, the game gets harder. There are many moments when you can feel unstoppable, like if you get some really good synergy, but every 12 areas you start again, keeping upgrades and the template for your Sipho, meaning you need to account early waves. If you get this game, give it some play time, and it will become a race to become perfect, and in the way of that is every failure. Tl;dr: Really good game design.