really good trilogy but the 4th game is isolated. The only few things it has in common with the other 3 are: graphics and physics. I felt the crystal system ended up getting me killed a million times more then getting stars. The cash upgrade system was stupid, I hate it, really REALLY bad idea. I CAN'T SHARPSHOOT MY UNIT HAS TO BE ON THE SCREEN TO SHARPSHOOT THIS IS SOO DUMB!!!! Last but never least: it did the whole game with only a mech and laser unit, also the moment I got the mech I sold the laser unit. oh yeah and all the enemies had way WAY too much health (at one point I had to hit a regular enemy 5 times with a mech punch to kill it) and the best units in the entire game(s) were removed. I.E: spy and tesla tank. plus the whole game is a missed opportunity. + if you think the next game should have multiplayer!