Research: platform game SDKs

Whilst looking for a more permanent gig, I am entertaining a side project in the meantime. Basically I am doing preliminary research for a platform game with a twist.

I was wondering if some of you have used any of the platform game SDKs out there. I have only found one that seemed mature enough to consider however I am probably using a rather narrow search criteria.

I found something called PushButton Engine. It looks pretty robust and open enough not to limit extension of the API. I was also wanting to look at something akin to/used in N ([URL=“”]link). I am not sure if N uses a particular library/SDK or if it was something proprietory.

One thing that this side project will utilize is alot of varrying height in the terrain with many sloping terrains at various angles. Also it will be very art-driven in that I will be expected to attach pre-rendered art to backgrounds, foregrounds and game sprites.

If you would be ever so kind to maybe rattle off some open source as3-based platform libs/SDKs with some info about what you like/dislike about them I would be very greatful.