Circle of Power

From BoardGameGeek:

Circle of Power is a free mecha-themed print & play game that you can play using ANY deck of cards. Yes, ANY! Print out a Fighter sheet for both players, grab some dice and cards, and you're good to go! Each Fighter has various Parts that they can activate. Attach cards to Parts to Charge them up. Once they're ready to go, Discharge them to unleash their effects, allowing you to do things like attack your opponent or disrupt their card economy. Discharging also generates Gauge, which you can later spend to activate more powerful effects. Reduce your opponent's life to 0 to win the game!