It's true we have an embarrassment of fantastic platformers on iOS, from traditional exploration style games to puzzle platformers to the brutal trial-and-error style of speedrun platformers. That latter camp is where Ravenous Games' League of Evil series comfortably lies, and right now you can snatch up every game in the series for just a dollar each during a limited time sale.
The original League of Evil [$1.99] launched in April of 2011, and at the time it offered some of the best controls for a platformer that iOS had ever seen. It was updated with new levels and some extreme challenges during the course of its life, but just under a year later and League of Evil 2 [$1.99] brought more of what made the original so great but with a slick new art style that was more well suited to Retina Display devices.
The art style change was met with a mixed response, but League of Evil 2 was still amongst the best platformers you could play. Its one big criticism was that it felt easier overall than the first game, and sure enough this past June the third in the series League of Evil 3 [$1.99] brought an increase in difficulty as well as a whole slew of new levels to master and a sweet new replay system.
Ravenous is currently in the middle of wrapping up a League of Evil 3 update which will fix some of the pesky launch bugs and add a new set of levels to the game. In the meantime, if you've missed out on any or all of the League of Evil series, right now is a great time to dive in during this limited time sale.