It's not bad. It lacks definition and such, but it's not a terrible level for someone of an amateurish skill level. The pathing is decent, can't complain too much there. Your cliffs are too small to judge, but for what you did, you did it right. Forests are fine, however the placement is questionable, but it takes a lot of experience to know how to place trees well.
You went a little crazy with the grass cliffs. I would calm it down with that, because you way way over did it. I like how you use the tufts of grass like I do, however you cluttered it together too much, and you could have more variety/better placement in your detail. The fences are amateurish, but I've met few people who can fence really well. They look alright, so don't worry about it. Good job only showing shadows upwards, I like that. You have some tile errors (specifically at the dirt path), but I guess the rust will shake off after a while.
It's not bad, man. It's kind of a boring level, there could probably be more for it, though as you said, it's for an event, so I understand that you can't put a lot of cluttering detail around because it'll make it difficult for people to play. Clean up the grass cliffs, get rid of the blue stepping stones near the middle of the level, maybe put a few bush fields in there. And work on those fences, you'll get them eventually.
Keep up the good work.
EDIT: Oh yeah, and in this situation, since it's hard to put detail to fill up the level, might want to use a little more tall grass, and make the patches bigger and actually group it. Also, in the middle 3 trees, remove the bottom tree, because it creates too narrow a path. (if it's a PK event)