Some initial thoughts; heard about the game yesterday and was pretty excited about it, got it about thirty minutes ago so I've already played a bit.
The designs are all brilliant - the monster designs are all very well done and the graphics as a whole, I can't fault. Some brilliant work put in to them, so well done
I did, however, get thrown off a bit by some of the writing - I don't know whether English isn't a first language or it was translated, but there were some real grammar errors in there which at the start of a game weren't great to see. It doesn't hurt the actual playing of the game though, but it's not an overwhelmingly positive start.
I started with Dodeed (I always start with the grass type Pokemon, so this is no different) and had the first battle against a Sealap. I'm presuming that a grass type move is super effective against a water type, since it does seem to do more damage, but there's nothing that says whether it is or not. If there was some clarification (or a "it's super effective"-esque notification in game) then that would be cool. Battles are pretty short ATM but I imagine that's because everything seems to be at a low level.
The IAP isn't intrusive to start, though I've already blown 10 coins on a second hatching spot since only one seems way too slow, given that you get an egg after every battle. However, it does seem you can sell your monsters to get coins back, so it's not going to be a case of just constantly having to buy coins since you can hatch and just sell off, even if it's only a coin every hour, it's still better than nothing.
Hopefully you're not stuck at the farm forever, it would be nice to do some exploring or battle some NPCs at some point, but we'll see what happens. As far as a freemium system goes, I very much like this one and I'm looking forward to seeing how the game progresses. Good start, with just a few niggles (the syntax and type effectiveness etc.) to iron out I'd say.