My procedural shmup Gall of the Thrall has been slowly improving. It still needs more graphical variation and perhaps some more base bullet patterns, but it's improving.
Here's my earlier post: https://plus.google.com/118357057412165387545/posts/4aPCCUdfMfz
The gist is the same. After every level, the player is given the choice to turn back. Once turning back, the player must complete as many levels as they finished before deciding. The player has three lives and no extends. Losing all three lives nullifies the score.
I've added a new twist by allowing the player to attempt more loops once the first is complete. The number of loops is decided by the number of levels which were finished before turning back.
Graphically, I've toned down the bullet trails because they made it feel too claustrophobic. I've reserved the brighter trails for a new type of circular bullet which does not get cancelled when the shooter is destroyed. This invention has been useful for maintaining the danger and forcing the player to use their bullet-cancelling trawl.
I've settled on a simple multiplier display for the partial scores. I don't tend to like numbers popping up amidst explosions.
I still have to decide on what to do about the player's shape. The random silhouette makes it hard to determine the front from the back. I might just bite the bullet and design a constant model.
Naturally, I'm skipping over the myriad of little tweaks that come with game development, but these stills can't manage to capture my pretty scrolling clouds either so frell it. ;)