It was good, the changing weapons button didn't work a few times so I had to press the numbers 3 times before it would change. But I only experienced this glitch near waves 16-17. Last boss was really hard. The skateboard machine gun boss was too easy. I thought he was just another enemy tank.
1) for the first few levels, the tanks take 5 quick clicks to kill. do so until you can buy the first tier for the laser.
2) Use the laser not by holding down fire, but by clicking quickly and repeatedly. Do so until the next tier is available. Take out the tanks that can target you directly first (1 cannon tanks, 3 cannon tanks, 9 cannon tanks, laser cannon tanks).
3)Repeat step 2 and go for the 3rd tier.
4) Buy an extra weapon slot and equip tiers 2 and 3 of the laser. Alternate between both when energy is out. Use level 3 laser for Carrier tanks.
5) Max out Weapon extra slots and buy 4th tier for laser. Equip all accordingly.
6) For Wave 17 (Last Boss), strafe along the opposite wall of the boss tank's position. This is the only time you should hold down the fire button. Alternate between the 3 when energy runs out. Avoid its homing blasts. Most of his mines will not be on the wall, but be ready to run across the map. ALWAYS RUN PERPENDICULAR TO THE ENEMY BOSS. Upgrade speed to level 4! If you get hit by his laser and his health is not below half, then you should suicide and replay the level. Use left over cash to repair ONLY IF YOU ARE SURE YOU CAN TAKE THE REST OF HIS HEALTH OUT! Meaning if he has over 3/5 of his health, then save your cash until he has less than that.