Hi there! Thanks for playing the game! I'm glad you liked the title haha :)

That is certainly one way to beat the game. I designed each cube with a role in mind - Red for big damage, green for healing, and blue for MP management and utility. I'd argue Blue is important if you want to win the game quickly, as Red is bound to run out of MP at some point due to Red Comet's high MP cost, and Siphon is the only way to get some MP back. I did a playthrough just now and accidentally let Blue get KO-ed too early (like, in 3 turns), so the game really dragged on for a while.

I think the Siphon spell could use a better design as a MP regeneration spell, but I imagine just making the spell the MP equivalent of Heal or Repair would be too boring/uninteractive, so I went with the current iteration (restore MP based on damage dealt).