This game resembles 'Runic Rumble',[1] which uses the same concept but requires the user to draw different shapes rather than connect elements in a fixed shape.
The first thing I did after seeing this thread and looking at the repository was to download the game from the iOS App Store (using an iPhone 5). I would have paid $1 to $4 for the app at that point in time.
I 'mastered' the levels up to but not including 'Belgarath the Bold' in the space of about 30-40 minutes, and seem to have unlocked all the spells except for superman, hot dog and teddy bear. That was entertaining - and repetitive. Challenges remain ahead of me in the form of Belgarath and Fionnghal, but unless some exciting new aspect to the gameplay emerges during those challenges, I don't think I would pay for an extension to the single player game. If I'd watched someone else play the game instead of playing it myself, I don't think I would now spend the $1 to $4 I would have otherwise been willing to spend.
My disinterest in paying for an extension to the single player game means I don't have any reason to consider paying for unlockable wizards, custom spells, or forums and betas.
OK - I wrote the above before trying the multiplayer game. Having now tried the multiplayer game, I found that to be much more fun, and much less predictable. Would I consider paying something now? Maybe. I'd be willing to consider one or two small in-app purchases that add to the gameplay in some non-trivial way without unbalancing the game between those who've purchased and those who haven't. I don't think I'd ever have any interest in forums and betas.
The main gripe I have with the game is not something you can easily solve: my finger gets sore after lots of frantic swiping on the glass. (It was even worse with Runic Rumble.)
Good luck!
[1]: https://itunes.apple.com/us/app/runic-rumble/id581952563
Edit: Just discovered 'superman'. Hilarious!