This is overall a great game, even if farming for your lvl 100 Pokemon can be a bit repetitive. I'm also stucked on wave 100 for stage 1-2 and 1-3, which is actually great, I just have to find a good strategy for it.
That being said, I'd love the game to have unlockables Pokemon when you get one of the achievements. They don't need to be gamebreaking but having a Pokemon which double the damage of your burn for example will be great as reward to get the Burn Achievements. And, obviously, getting to try those legendaries once you defeated them.
Thanks again for the great game !