Kinda fun. Few points: Work on graphics of course, but it's not too bad. You should include in the instructions you need to click on the cannon to grab it. Also why use the A key? Why not click the mouse? And the upgrades are really easy get. By wave 10 I hate level 100 in everything with 400hp. :P
Good concept, and I do love Stargate. It's a bit hard to make out groups sense the pictures look so much the same. Keeping with the theme you could use the gryphs form the gate, and use different colors, then it'd be a lot easier to see.
All cards are removed. King Heart/Diamonds, Queen/Jack Clubs/Spades, and removing the Ace. A classic illusion sense most people don't notice the suit changes. It's be nice to have buttons to answer Yes/No.
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