Nice idea. The art is very cute but the gameplay needs a little tuning because it takes way too long to fill the meter. This may be by design for the mental health message but it comes off a little tedious. I think one thing you could do to help is to make the clouds red and green with white +/-. That way it's more immediately clear which is which so people don't accidentally shoot the good thoughts just because they see "cloud". The sound effects are perhaps a little severe but otherwise it's a really nicely made game.