Crystal Keeper

From Absolutist:

Crystal Keeper is a new 3D arcade game. You will have to shoot hordes of monsters of every kind, which will try to steal your priceless magic crystals. An excellent chance to relax and spend some pleasant hours enjoying the game-play. Three skill levels for advanced players, and unlimited game levels included. Best players can take part in the online contest. Both installer and uninstaller provided. Excellent 3D graphics and sound. Free e-mail technical support and upgrades for full version. There are two playing modes: Arcade and Timed. In the Arcade mode your task is to keep the crystals in their places. The more crystals you manage to keep, the faster your life magic grows. When it hits the 100% mark, you are taken to the next game level. Be sure not to let it drop to zero, otherwise you will have to start from the very beginning. In the Timed mode you are just given 5 minutes to play - try to kill as many monsters as you can. Crystal keeping does not matter much here, the main goal is to gain points and to top the score table. Your results are stored separately for each skill level and game mode. You can always publish the best score on the Net from the Top10 window. Make sure your Internet connection is up when you hit Publish.