It is way too dependent on Hardened Scales to get the critters big fast, yet it can be a lot of fun.
Here is a game in which it was all about who built the biggest army, or in this case, the biggest critter, and I lost that contest.
Here is my opponent's big critter with 50 +1/+1 counters on it (Warden of the First Tree) doing it thing.
Here is a game I won. If I get even just one Hardened Scales out early, I am in good shape.