Kosamin Ruins is the first stage in The Endless Wood. This stage is a remake of Sesamin Ruins.
Battleground
Gabriel spawns every 6~20 seconds, while Snache and Those Guys spawn every 3~20 seconds. Attacking the enemy base will spawn the boss, a trio of buffed Winged Pigges.
Strategy
Four Meatshields and Ramen will help to form a strong defensive line against the Winged Pigges.
The level begins with only the peons, so as the boss wave operates on base-hit, use one Ramen at at a time to stall the peons without moving forward too far, and use that time to get to MAX Worker Cat and max money within that wallet level.
A combination of angel or all-enemy-slowers and/or knock-backers will keep the Winged Pigge trio at a safe distance, and although it would take a long time without massive damage, this is a safe way to complete the stage.
Just make sure everything you bring on that second row can outrange the Winged Pigge, else they will decimate it within seconds and you will lose.