"Whale Trail" won't convince you back into the infinite side-scroller genre if you've written it off for good, but if the occasional infinite game has become your guilty pleasure, this is definitely one to check into for its great physics and exquisite level of polish.
It's such a breath of fresh air to find an infinite side-scroller that doesn't feel like "Robot Unicorn Attack" or "Canabalt" all over again! But do the developers meet their stated goal of unifying casual and hardcore appeal, or fall just short of it?