I usually avoid these types of iOS games like the plague but I had enough gold coins to get it for free and something about it really kindled my nostalgia of playing NES games in the 80s so I picked up Goblin Sword. Glad I did. It doesn't do much but what it does it does well, and I love finding secrets in the short levels. Good stuff.
Glad you are enjoying it. There's a lot more depth to the game than the initial levels. It gets more challenging finding everything and there are a bunch of things to find/unlock as well as various weapons which change how you play. Plus all the achievements to go back and finish certain levels at a specific speed or to try and finish levels without doing certain things... it's good stuff. I won't say it's the greatest platformer ever, but I found this much more enjoyable than a most of the retro inspired games today.