Woodstock is the 12th level in Serious Sam 2.
Sam continues his fight through the Zixie's home. After riding a lift through the industrial part of town, Sam manages to reach the ritual site. However, before he can grab the Medallion piece, Zum Zum steals it. The Zixies offer to help Sam locate Zum Zum, which he accepts.
1. After getting off the lift, find the tree that's straight ahead of you and walk to it's back. On the tree's back is a platform suspended by a wooden plank. Shoot the plank, and it will collapse, dropping a Serious Damage. Pick up the Serious Damage.
2. While at the village after the lift, start walking left from where you entered the village. Eventually, you will find a bridge. Follow the bridge to a tree trunk, then go behind the trunk. There will be an opening with a Bull Soldier in it. Kill the Bull Soldier, then go inside to register the secret. However, there is a Treasure Bag on the top of the stairs, and to the left of the top-most stair on the ground floor is a switch. Press it, and a platform with a Treasure Chest will lower.