Old platformer in forest theme, hit mobs from the bottom

[FistinPenguin]

I'm looking for a game I found on a demo cd on Windows (I played it on Windows 95, don't know if it worked on other Windows versions), and I played the game around the 2000's.
It was a 2D platformer where the level setup was fixed (you saw the whole level, moving over the left edge made you reach the right side of the screen).
Each level also had a fixed amount of mobs that spawned. In order to kill them you needed to hit the platform they were on from the bottom with your head. This immobilized the mob and you had a few seconds to walk over them in order to kill them.
In order to complete the level you needed to kill all the mobs.
After a few levels you had a boss level with a single mob, but don't know anything more about it.

If I recall correctly, the platforms bumped up when you hit them, or they bended in the middle; I'm almost sure they at least moved. I think the platforms were also blue.

All the levels had like the same forest theme. I believe the characters/mobs were like troll/gremlin-themed. But that can also be just the first levels