Oh, really? I always thought it was more of a zen-atmosphere game. It's actually a challenge?
I didn't play many, but it is hands down the best Metroidvania I played.
The game is mostly exploration with puzzle solving to acquire powers that let you 'open' new areas (they are HUGE) alternated to action/bosses sequences that can be very frantic.
It's really relaxing at first just enjoying the scenarios, the music etc...but it gets quite involved later on.
There is a fantastic story too, with a couple of twists and even an optional story part.
There is quite a nice crafting part too (you collect things in the sea that you can cook to create other things that help you).
I enjoyed Aquaria for a while but got a bit tired of it. It just keeps going on and on.
It IS super long...I played it long ago but I remember the story really picks up 6-10 hours in.
Maps are massive, and there are a LOT of them...many you can go pretty early that are incredibly difficult (you will have to return later to them when more and better equipped).
Aquaria is great, but I didn't like the iOS controls. Your hand keeps blocking the view.
I didn't had problems during the 'normal gameplay' (exploration...it was the classic drag to move contro scheme (so yeah your hand can cover the screen)....generally it's very relaxing and calm, and I did take my time to witness this world between my hands, but some bosses are pretty difficult (last one comes to mind) and controls din't help.
You must change powers on the fly pretty quickly in some cases and it's a bit slow.
I remember I died quite a bit due to controls on last boss, but I wanted to know the end of the story and I finally managed to do it (didn't help the last sequence is the classic 4 bosses in a row without healing or pausing).
Nevertheless it's overall a nice experience and a game not to be missed imho.
But I'm always a bit hesitant to advice More Badass a new game (and a long one too) when he already has almost all AppStore in the backlog