Good co-op twin stick type games?

With the recent release of Gauntlet, my friends and I have all gotten into games like this. We beat that, then moved onto Forced, which was alright, and have now recently been playing Hammerwatch which we're enjoying quite a bit.

Aside from those, we've had a somewhat tough time finding other stuff like this on Steam. Any other games that feature similar gameplay and have 4-player co-op?

Here are some suggestions. They link to my wordpress site for games that I had in my list but were removed when the forum changed due to the editor errors.

1) Super Smash Land - A freeware demake of Super Smash Brothers - http://freeandlegalpcgames.wordpress.com/2014/01/01/super-smash-land/

2) Uberleben - This is small favorite around my home 1 to 8 players parachute down together while trying to avoid obstacles. In the settings - you can make it more difficult with spinning tunnels and fighting as you go down.

There are more but these are the ones that come to mind for 4 players.

Binding of isaac rebirth that's coming next month is going to have local co-op, but from the videos I've seen it's only 2 player.

Also Spelunky (but it's not a twin stick shooter but fun co-op game)

Geometry Wars 3 has some coop modes.

Screencheat

https://www.youtube.com/watch?v=CBhx6CPYgHI