I must say, for a 2-day time limit the game's pretty good!
The graphics are simple but completely functional, and the gameplay is quite enjoyable. Maybe catching a cow could also increase the time left? That might make the goal of catching all the cows more attainable.
I like the spaceship controls, but personally I'd prefer if acceleration and the lasso were separate inputs. I understand this might be intentional design, but I simply dislike the loss of all control when you inevitably run out of energy.
But I must say it again - for such a short time limit, you've done a really great job. Congrats!