The original Guacamelee! is one of my favorite "Indie" games that I own, and I was extremely excited when I heard that the Super Tubo Championship Edition came to PC. I purchased it immediately and just finished my Normal playthrough.
Guacamelee!: Super Turbo Championship Edition adds a good amount of extra content, in the form of new levels, new enemies scattered throughout the game, a new boss, and new abilities. It's a "Metroidvania" style 2D action game, but instead of a bounty hunter or vampire hunter, you play as Guacamelee!, a luchador fighting his way through both the land of the living and the dead to rescue his love.
*Unique art style drawing from Mexican folklore, specifically the "Day of the Dead"
*Great music and environments
*Clever, rarely frustrating platforming sections
*Fun combat, with a mix of combo-based striking and grappling
*Simple story with humor and references to classic games all over every stage of the game
*Can't remap controls on a controller. This is a minor gripe, because the controls make sense, except for the new "Intenso" mode, which requires pressing LS and RS simultaneously on a gamepad. This is annoying, especially considering that RB and RT are both mapped to the same function, and either could have been switched to Intenso mode.
*Game is short. I wanted it to last longer. There is replayability in a Hard mode unlock and a challenge guantlet of sorts, with lots of hidden items to go back and find for 100% completion. But even with the added content, I beat the game in 9 hours (not 100%), with a considerable amount of backtracking and exploration.
*The new Intenso mode makes combat far too easy on Normal playthrough. Entering Intenso mode lets you just wail on anything until it runs out, forgoing combos and dodging entirely.
Overall, I'd highly recommend this game. As an owner of the original Guacamelee!, I received the upgrade at a discount (67% off, or $5). I had no issues replaying the game from scratch, because it's fun. I'd be less likely to recommend the upgrade to existing Guacamelee! owners at $15, because there's not THAT much new content. For new owners, however, $15 is absolutely worth it, even with the short length of the game. You'll want to get 100% completion, and then tackle Hard mode if you still haven't had enough.