UPDATE

The Upgrade Screen area has been revamped behind the scenes to be more expandable in the future. In addition, the upgrade interface has been updated to show the soul costs and to show short tooltip descriptions of the various upgrades before you buy. Also, there are three new units to unlock and one new spell!

The Unit Summon interface has also seen an overhaul to show the costs and display tooltip descriptions of the units being summoned.

There's also been lots of various fixes and balance changes. Hopefully the game is less crushingly difficult now. There's still a long ways to go before this is fully playable, but it's a start!