Nice game all-around. I would love a pause button, and also a restart level button. Sometimes I'll lose my blue ball early on, and I know I won't win, but have to launch all the ghost balls and wait for them to bounce back, then back to the menu and start over again.
I wish there were either an in-game list of weapon/armor attributes (i.e. of evasiveness, of smiting, etc.), or some way to see the text of what a particular weapon does. For instance, I've got some axe of blasting, but I don't remember what the blasting attribute does, and it doesn't tell you when you select the item in inventory.
I really don't like the fact that you tend to fall off of stuff if you're standing still. If you stand near the edge of something, you'll just start to slide off the edge.
Good game all-around. I'd like to add my support for putting in hotkeys for selection. Also, it would be nice to have the name of the building (and maybe its upgrade status) added to its health info when you hover over it.
The second set of missions is tough, but not too terrible. Hint: use advanced fighters instead of cannon defenses first, if you're having trouble with 2.5.
I think the third set of missions needs a reworking though. All you really have to do is spend all your resources building basic lasers, spread out a bit, and you win. I think it would be better to make some new structure to produce the infection/capture bullets instead of basic lasers.
Nice game, I like it all around.
I also did have the problem with spells, where I end up with blank spells in slots that I can't use or replace with new spells. It just says 'use an empty cell to swap items' and won't let me put any new spells in.
I'd really like to see a 'Spar yourself' button inside the Arena tab. Right underneath where you select your Active and Defense deck, there's plenty of space. You would just use your active deck to fight your own Defense deck, and test it out/tweak it.
Would be nice if you could swap out your active heroes. So let's say you've got a horseman that you don't want to use in a particular battle, there should be a little hero bar, so you can have, say, 5 extra slots. You can swap your active heroes in or out depending on what you need. Would also give you the chance to experiment with more classes and army configurations.
Bug:
When shield expires, there's some sort of bug where you lose your turn, and it immediately skips over to the next person without giving you a move/shot. Mostly noticed this when there are 2 or 3 players, doesn't seem to be a problem when there are 4 (shield expires before your turn).