Some upgrades cost a lot of cards and gold and give nothing in return. Really annoys me to keep them at level 1. I know it's harder to balance them like this but please try. It takes a lot of hype in my part. It can be more challenging to balance as you add more variables in cards and definitely mistakes will be made. Yet this is the way the game will grow.

My recommended changes include: adding more variables to change to spells, changing starting stats, adding unlockable new features(like the shaman token: ability unlocked at 2). Enjoy.

Meaningless Upgrade // Recommendation

Freeze Ray: Has initial range of 2. Affects all units in range. Effects last 4 seconds all levels. Very minor range upgrade(0.1) per level // Initial: Range of 1.2. Affects all units in range. Effects last 2.5 seconds. Every level Range increases by 0.4 and effects last 0.6 seconds more.

Hyperdrive: Affects all units. Effects last 6 seconds. Doubles speed. Very minor effect time upgrade(0.1) per level // Affects all units within 2 range. Effects last 3 seconds. Range increases by 1 and effect time increases by 1 per level. Every level hp increase increases by 35 and effects last 1.5 seconds more.

Mind control: Affects 1 unit within an area. Effect lasts 7.25 seconds. Very minor effect time upgrade(0.25) per level // Affects 1 unit. Range is 0.5 for precise selection. Initial: Effect lasts 4 seconds and gives a health increase 25(like the robin tweek buff).

Power Bind: Has initial Range 2. Affects all cards in range. Effects last 40 seconds each level. Very minor range upgrade(0.1) per level // Initial range 0.5. Affects 1 card for 15 seconds. Range increases 0.5, affected units increase 1 and effect time increase 5 seconds per level.

Purify: Has initial range of 2. Affects all cards in range. Removes positive buffs from allies as well. Range increases 0.1 per level. // Has initial range of 1.5. Range increases 0.3 per level.

Unholy combustion: Kills an enemy unit deals 14 damage to surrounding units. Damage increases 4 per level. // Initial cast delay of 3 seconds(make it feel like an unholy ritual). Delay decreases by 0.6 seconds per level. Damage dealt is 1 at start. Damage increases 15 per level. Unholy rites: Gains ability to cast unholy combustion on another unit affected by the blast at level 4(%10 chance) Chance increases %10 per level.

Transmogrify: Changes enemy into a rat and decreases level by 0. Decreased level of rat increases 1 per level. // Initial: Changes enemy into 2 rats. Doesn't decrease level of rats. Decreases level of rat 1 per level. Rats decrease to 1 at level 3. And 0 at level 6.

That's all. Hope it helps.